To the export/import, all I can say is: NICE! I've been fooling around with it for some time now and trying to break things, but so far nothing came up.
I noticed a completely different issue though which is again related to multi-acount users. As you probably know only one account can use the pet battles at a time, even if 2+ are online on one battle.net. In the standard UI this is indicated:
Hovering or trying to do something with the pets gives an error message saying that only the first logged-in account can use the pets.
Using Rematch however this whole section is overlapped of course. Swapping pets is non-functional with no indication or messaging of what's going on.