So what might have been Elan's super secret plan?

[KorvinStarmast]

X-Men: First Class is a good movie, although there are enough continuity issues between it and the earlier movies that some people don't consider it a prequel.

Well, as prequels tend to be made after the original film, and take place chronologically before the original film, and given that you readily admit that these two facts apply to TGTBATU, I'm more than a bit confused as to how you don't already acknowledge that it's a prequel.

He wasn't referred to as Blondie in either of those two films.
What is your source, or your basis, that it takes place before the two Dollars films?