>>544703057
>>544703085
I'm not sure how this works, but I know gacha games can hire writers of other places to write specific chapters and the like (FGO hired I think Amphibian for the Van Gogh event, Last Origin hired Urobuchi for Kheshig's. So working somewhere else doesn't mean you can't work in another thing.
Buuuut if he is the writer for Trinity Summer, and therefore at very least Justice Task Force if not Tea Party, this means he is among the more important ones. I don't think it's feasible to assume he'd be writing in another game. At least not as a core writer.
>>544703092
No idea; JP only. Global should get in 1~2 months.

>>544063074
I mean it's a korean company right? Last Origin and Nikke have really fucked up worlds with ton of combatants decapitated and torn to pieces. There is also a ton of dicking around when they aren't progressing the main story proper like in Events or in breather arcs.