the 3 TO and landings don't have to be at the same time, they just have to be within the last 90 days.
Yes.
What trips up some is that both the TO and the LNDG have to be night to count night, not just one or the other.
That's a very good question!! I am suprised it isn't asked more often; maybe because it's relevant only to people who are doing a departure shortly before sunrise, which almost nobody does in GA.
I don't think the takeoff and landing have to be on the same flight.