1) Yes, it will be ok.
2) No issues also here.
3) Yes, you can attack with the hero. It's also fine.
2) okay. How we can plan any other massive off operation (dont forget its final server, with only experienced player) with same arrival time? Or i dont understand yours answer and if 1 player send spam he will be treated, and if this do from many players - all be ok?
I mean 1 player sent 1000 attack or 250 player send 4 spam attack with 19+1?