So this is sorta off-point but will lucky egg be a gift item in the game? It's been available since b/w and it's near impossible to find it on chansey(i'd know, i always obtained one in platinum taking 3-5hrs.)
Is lucky egg still relevant to your playthroughs? Would it make any difference if it wasn't included in oras?
Briney will take us to Orre to snatch it from Micheal at the last moment.
I never really made much use of the Lucky Egg myself, outside of completing my dex in Diamond, even after it became standard to get one for free. But I don't see it making anymore of a plot difference for the Lucky Egg to show up at some point than it would to replace the Exp. Share with the Exp. All, which I would not be surprised to see, given the fact that for them to revert it, it would have to become a hold item again, and thereby open it up to be sent back into Kalos.