Honestly, if they make a new DOAX3, they should add ALL the girls in, not just the cut girls, but also the DOAXVV girls released thus far. Don't limit it to just two new girls.TN could release a new DOAX3 on PS5, with Tina and the DOA5 characters but I hope it's not like Scarlet.
At least Misaki, Nagisa, and Tamaki's nationalities are confirmed (though to be fair, it was already pretty obvious those three as well as Sayuri and to a certain extent Kanna were Japanese since the prior four had hiragana names, and in the case of the latter was an Oni, which is not known to exist outside Japan). We don't even know Monica, Fiona, or Luna's nationalities (not canonically at least. We can at least guess that Fiona's British, Luna's Russian or former Soviet-bloc, and Monica might be Romanian based on certain hints).