Archangel's power description reads as follows:(Passive) At the start of turn, deal 351 damage to any Airborne enemies and stun them for 1 turn.
So my guess (and it is just a guess) is that the power might be bugged if the launched character was due to return from airbourne the next round - the stun normally grounds them but as they were coming back down anyway there might be an order of operations issue. The answer would then be launching for more rounds.And yes, 5* & 3* Angel's are playable together, supposedly because they don't share a name in common like the Cap/Thor/Irom Man/Wolverine's. It doesn't really make a lot of sense.
You cannot hurt enemies in airborne state but you CAN hurt them if they are stunned instead. So in this case the combo doesn't lose its value COMPLETELY (as you can now hurt the enemy for 1 turn while its stunned, instead of airborne) but does lose some of it (the total disable duration is reduced by 1 turn).