I want to add that some "stereotypical" names are actually not as common as one would think. This is something that readers familiar with the country in question will notice, and is sometimes the main problem with stereotypical names.

For example the Russian name Ivan: I've never actually met a Russian named Ivan. I have met Russians called Alexej, Sergey, Wladimir, Sasha, and Andrei, however. None of the Russian authors I read and love have this name (Fjodor, Arkadi, Boris, Leo, ...). I don't know for sure, I think the name might be an outdated stereotype, i.e. the name might have been common once but not anymore, or it might be a name that is more common in a specific social class, the working class for example.

It's the same with some German names like Michel, Fritz, Franz, Otto, Hans, Heinz etc. that were common up until the early 20th century, but now are much less popular. (Though some German names have had a comeback, for example Anton.) Here it might be related to the Third Reich and how typically German names left a bad taste with some people in the aftermath, but I don't know for sure. In any case Germans in foreign literature still often have one of these names, even if the novel is set in modern times, and it's always jarring. Biblical names like Tobias, David, Simon, Jonas etc. are now much more common.

So I would say that using stereotypical names is not necessarily bad form, but you have to know where the stereotype comes from, and if it is relevant to the time period your novel is set in.

I look for popular names, but not the MOST popular names. For example, I just googled "most popular names in the UK" and found this at the top link. An excerpt:

Boys

Oliver - 6,259
Harry - 5,031
George - 4,929
Noah - 4,273
Jack - 4,190
Jacob - 3,968
Leo - 3,781
Oscar - 3,739
Charlie - 3,724
Muhammad - 3,691

Girls

Olivia - 5,204
Amelia - 4,358
Isla - 3,373
Ava - 3,289
Emily - 3,121
Isabella - 2,627
Mia - 2,590
Poppy - 2,527
Ella - 2,452
Lily - 2,405

Just pick something not in the top 5, it would be realistic, but not obviously stereotypical of the region.

The problem about this is that most of the time we want to read something about special people. Sure, we want to be able to sympathize with the character and for example superhero comics have a history of making it look like everyone could be Superman - or Shazam the 14-year-old-boy-transformed-into-a-superhero - but characters in books, comics, etc. tend to be special in some regards. By giving your protagonist a name that seemingly every second person has they can appear quite boring.

What name do you think would be more memorable: "Shazam" or "Billy"?

Yes, the protagonist in the linked comic series is named "Billy", quite the typical name. But most people will likely find his superhero form more memorable. Maybe you could use this and give your "Juan" and "Maria" interesting and memorable nicknames. Especially if they have a name that seemingly everyone else around them had that could be a reason to try and stand out. How do your characters feel about their name? Do they like this typical name? Maybe they like the feeling of proudly representing the majority. Or maybe they want to be special. Different. Not just another "Juan" or "Maria".

A lot of this depends on the setting. In fantasy or sci-fi settings it's far easier to just come up with new names. In modern day settings like in a thriller you will more likely use "normal" names. But this also depends on a lot of factors. Are you in a rural area where older names are more present? Or a metropolitan city with influences from all around the globe? Is the social class of your characters focused on traditions or innovation?

As you mention that you have a setting with lots of people from all over the world you could use steretypical names a few times. Maybe one or two out of a group of five people would feel like something that can actually happen while still not feeling as if you were simply too lazy to look up other names. But you should think about other options to refer to these characters and you should think about how the characters feel about their own names.

It is bad when your "national" character is one-dimensional. It is perfectly fine when this character is non-stereotypical.

Creating a "representative" characters with stereotypical names is a bad (and well-worn) practice when those characters also reinforce popular stereotypes of a certain nation or racial group. On the other hand, if such character has depth and well-developed, steretotypical name becomes insignificant.

This trope was humorously subverted in the 2002 movie The Cuckoo, in which one of the main characters, a Russian, has name "Ivan", but his newfound friend, Finnish sniper Veikko is not believing it because

when they first met and Veikko asks for Ivan's name, Ivan replies "Get lost!" (in Russian) - and this is how Veikko had called him ever since.

It depends on what sort of story you want to write.

If you want your character to stand out (superhero, famous outlaw, rebel leader, etc.) it's probably better to pick a name that stands out.

If you're trying to show that this is an ordinary person, living an ordinary life, then using something more common can be an effective tool. Think of Winston Smith from 1984 - his last name's meant to sound like a generic, boring British guy. There's nothing particularly remarkable about him. He's a guy who tries to rebel and fails.

A generic name can also be an alias meant to make an interesting character sound less remarkable (spy, secret agent, etc.). For example, John Reese in the TV show Person of Interest.

There's the humor angle, too. Maybe you're writing about some poor guy named "John Doe" that no one can take seriously.

There is nothing wrong with using common names for characters unless you over use them. If everyone has the most common names for their region, the readers may start paying attention to that instead of your story.

That being said, there are ways of playing with it. You could use it to break expectations. Maybe Ivan is from the UK?

Heck, any of them could be from the US.

Maybe have two characters named John. One will end up being called by a nickname. My name isn't incredibly common but for one event we had five people with my first name on a radio net. That was a fun mess. With 95 people on the radio net, last names were out as well.

Maybe have John meet Juan. Having the "same" name might be a running gag for the two.

Just to point out, that the names John, Juan, and Ivan (along with the Irish Sean/Shane, Scottish Ian, the French Jean, the Italian Giovanni, the German Hans and many others) are derivations of the Hebrew name Yohanna which means Yahweh (God) is Gracious. Many of the most common Middle-East and European names are derived from Biblical names. John is so common that I'm not sure if you realized that the names you selected are all John-equivalents.

Non-Sterotypical Names tend to be Americans in fiction from outside the United States (If you've watched any BBC shows, like Doctor Who or Top Gear, when an American appears, expect someone to guess their American from the name alone, because it's a weird one). America, being a melting pot culture, could have a odd cultural mashup of names that could be because they are a mixed nationality family following a traditional naming convention (Irish families tend to name first born son in a convention that the first name is the child's paternal Grandfather, second name is child's maternal Grandfather, family name... if an Irish man marries a Hispanic woman, than the name could be Sean Roberto O'Reilly... and that's not assuming that they can always give the kid a Russian name for no reason beyond wanting to be different).

European names to Americans tend to be stereotypical because, well, an English family is going to name their kids English Names, and the French Families are going to give their kids French Names, and the German kids will be given German Names. And each society tends to have rules about naming their kids too.

If you look at any group of people, some will have very common names, others well known but less common names, and a few will have unusual names. If your own characters also have a mix, you're fine. You don't want all unusual names or your reader will have trouble remember them. If they're all top names, that isn't realistic (the top names aren't the majority of names).

Most of my modern-day characters have well-known names because the rest of my characters are from ancient times, in other parts of the world, and their names are unusual. So I needed a balance.

If you're careful that the common names you choose are actually popular in the real life setting you're taking them from and not stereotypes elsewhere, you're reasonably okay. This is hard to suss out but one example could be Juan in the United States, even though it's a real name here and in countries that are majority Spanish-speaking. (Note: If you're American and old enough to remember certain coffee commercials (though that's not the only source of the the stereotype), you probably see my point.) Just like you'd want to avoid making the only Jewish characters in a story Abraham and Sarah (unless of course it's a Bible retelling).

I would also avoid making all the names from a region super common ones, even if they're not stereotypes. Why make readers from those countries or with that ancestry wonder why the other characters are so much more interesting?

Choose names that have that countries "feel" with out being stereotypical (e.g. Alejandro -Mexico, or Aleksandr -Russia)

As I interpret it, your main aim is to have the character's country of origin obvious from their name ("strong sense of location with the names"). Stereotypical names will obviously do that, but as others have pointed out, these names may not even be popular in this day and age and having too many stereotypical names may make the story and characters seem less... complex?

So why not look up names online and pick ones that are not stereotypical names but still have that countries "feel" to them. For example when I look up Mexican girls names I see that Maria is number one (and very stereotypical) but plenty of the others "feel" Mexican without me ever having heard the name before (or rarely): Juana, Margarita, Verónica, Alejandra, María Elena...

You could also just pick a common name (e.g. Alexander) and look up that name in Spanish or Russian (Alejandro -Spanish, Aleksandr -Russia). Again I've never met an Alejandro or an Aleksandr but I could give you a good guess as to what part of the world their name is from.