Answering own questions:
Yes remote play works. Pre-built elf is ok, no need to build or supply key.
Chiaki kept failing me with "Invalid PSN ID". Made new user then pairing worked. Dont know why but now very happy.
Have Switch @1.0.0 and need to get at least 1 game ('Puyo Puyo Tetris JP') to have any sorts of fun ahead. So I'd rather get a 2.1.0-game like 'Arms' or 'Mario+Rabbids Kingdom Battle' even knowing CFW might take longer to get. But will those games require me to update FW online? I mean ...
Is...