Negative Zero > for that combo, vs Rouga it seems better to do ground string > IAC > j.5A > j.5C (2 hits). Works on Senna as well.
Infinites:
Kunagi vs Rouga (anywhere ok) (VERY hard)
ground combo ending with 5C (1 or 2 hits) or 4C > 214A C > j.236A > j.5A > land > repeat
The 214A C must be done as fast as possible, or else you won't have enough height after the j.236A to do the j.5A on landing. If you do this in the middle of the screen, sometimes when you land from the j.236A you're on the other side of them, so possible mixup?
Senna vs Rouga (anywhere ok) (quite tricky)
5B > FAST j5B > j5C (only the second hit connects, so delay your next input) > j5B > land > 5B
It's tough because the j5B must be done immediately or you miss. You might be able to do 5A > 5B on the ground but I think it will knock you too far away. 5C is out of the question.
note: this might stop after 3-4 reps. I've been unable to go beyond 3, and you might get pushed too far back to continue.
Senna vs Rouga 2 (anywhere ok) (really hard) (new)
j5C > slightly delayed j5A > j5C > land repeat (no need for ground hit, just jump again)
It works even if you start right next to Rouga. The first j5C must be super fast or else it just completely misses. My record is 5 reps on this, but distancing looks like it should be infinite.