Taion actually addresses her as Nami-san constantly

So even more generic bad translation, they just turned the "san" into Maam and called it a day. To think I gave them too much credit.

but now it's kind of inconsistent with the previous games, since none of them had fake swears.

I'm not far enough in the game to say for certain, but the entire gameworld feels enough like a seperate entity to have its own speaking styles. Much the same way that every Titan in 2 had a completely different English Accent randomly, whereas here they are are intermixed.

Regardless, I find it quite amusing because instead of going the full route of making absurd idioms and phrases be shouted constantly, they just word swapped. Making it very easy to substitute it back. Which works because Lanz feels like the type to actually just swear constantly, but if he did the ratings board would have a fit.

some fairly explicit things around Tora and Poppi that were changed

Considering even in this tamer version people got pissy about their relationship, I never doubted it got turned down. Keeping Poppi's naming scheme after elementary and middle school girls would have blown fuses everywhere.