I don't understand the Swallot but the other are good ideas
Still waitin on that Dragon/Fairy MegaAltaria....
Ive never really liked Latias or Latios to be honest.... If had to choose though, id probably go with MegaLatias>MegaLatios cuz if u wanted to use both Soul Dew on Latios still outpowers MegaLatios amiright? Idk if i am or not, legitimately asking (looking at you, Dirge)
@ Nick: Like i mentioned above though, Altaria, if any of them, should become Dragon/Fairy. I was thinking Dragonite should at first but imo i think Altaria would fit the bill better.