User blog comment:Lex wa Kaiho/What is Lumen Histoire?/@comment-26399354-20130627162312/@comment-7418318-20130627163215

No. That crossover was just a gag you could say.

The rules of magic and timetravel work quite differently in Rave and Fairy Tail, not to mention that we get to see the full world map of RAVE and there is no Fiore there.

But considering that Edolas and Earthland have different laws of magic too, I suppose it's possible that the RAVE world(s) are also parallel universes to the Fairy Tail ones that might be reached via portals just like they used anima to travel between Earthland and Edolas.