Cyclonus having been Bombshell is more 'canon' than the other option, I believe, and that's what I tend to go for more--partly because I find the Insecticons more interesting than the Seekers.

Though in RP usually I go with him having been a mix, because it's funny to have him looking at Skywarp (and/or Bombshell, although I've never had the opportunity to do that one) and being all, "...I was created out of you?"