I would also like to see some same pilots in different ships. As booster packs of course. For example Tycho Celchu in an X-Wing (with the same pilot skill probably in his case but perhaps with a different ability, idk) would certainly not be wrong, since he flew an A-Wing pretty much only during the Battle of Endor. Another example could be new additions from the expanded universe. Rogue and Wraith squadron offer so many shining examples of interesting Pilots (as do their inperial counterparts) there should be no difficulty finding people they could use.
I would say yes to pilots that cross factions too because a lot of them actually did change sides during the conflicts, but it would get problematic regarding their uniqueness. Although you can on tournaments also have the same pilot twice if you play Rebel vs. Rebel or Imp vs. Imp. In friendly games you could just find a solution together who flies Boba Fett and for which faction. Then it would be okay.
Without wanting to heat up the discussion again, i would not mind if FFG would expand not only to expanded Universe but also to Episode 1-3 Stuff. For tournaments you have mirror matches anyway so why be against Old Republic vs. Rebel matches or Empire vs. Separatists… and in friendly games you could just decide if you wanna play thematically or with factions pitted against each other that could not have been because they didn't exist in the same era.
I would honestly rather see that happen than them digging out very unknown and perhaps impopular galactic civil war era ships.

