The game is still installing for me, and maybe I'm just not seeing them for some reason, but will this game ever get achievements on galaxy? I'm a little disappointed that there doesn't seem to be any even though the game has some on Steam and other games have them on galaxy. What's up with that?

Hard to say. Some games, like Witcher 2, still don't have theirs. And their are here for quite some time. Then again, it's still beta of Galaxy... and they still working on much of it, so who knows? As for now - no. :(

This game's GOG version is apparently outdated. Japanese text support was another addition for Steam.

False . GOG version is newer than Steam version of the game . Because on Steam , English and Japanese versions are using completely different builds . You could check depots . Yes latest version is Japanese one on Steam but English version is still remain as unchanged on Steam even older from GOG version .

So no achievements period for the series?

Now it's 2019, and the original PSP/Vita Achievements/Trophies are still not available to players on GOG, despite being available to players on Steam.
:(