for (1) - you probably want multiple things going on! i'd definitely consider watching some mecha anime. there's rarely just one thread of action happening throughout.
for (2) - it depends on how you're doing it. blitz, duel, or a relevant strive could all apply.
(3) - strive is its own action. you always have 3 dots in strive
(4) - they're always locked! ofc you're always free to say something doesn't require a roll, and thus a locked action doesn't matter