Maybe might be special battles like in P5? can only speculate as of now. We'll see I guess... timeline wise since all Persona games are somewhat connected, it wouldn't make sense if you could fight him haha
Yep, in OG P3 he is voiced by Yuri Lowenthall (Sasuke) if im not mistaken. For P3 reload, he's going to be voiced by Aleks Le, who also voices Zenitsu from Demon Slayer.