As Much as I'd like for this to happen, I unfortunately I don't think thats very likely. While I'm fairly confident that Collin and the other Cherubs will return in some compacity (maybe as a revenge plot against I.M.P for getting them kicked out of hevean or just a follow up on what became of them), Loona was largely disconnected from that story and thus the writers probably won't included her in anything having to do with Collin or Cherubs as a whole.
MAYBE if this ship gets more popular and theres enough Fanart of it that it eventually reaches Vivziepops attention she might make an allusion to it or give them some interaction in a laterr episode, maybe? idk how Vivziepop feels about how overly shipper her characters are to begin with.
For now Collin/Loona ship remains in fanworks