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Yep. So there's nothing much in regards with discussing the compatibility.
For all we know, official in-person tournaments (VGC and the like) might just use ORAS exclusively (meaning your 'mons must be BORN in ORAS, but can be traded to XY if needed for something and back). Think of it as an...
Possible. Considering they made a patch for a bufix.
The other possibility is let the ORAS cart do all processing work, have the XY cart display generic/close animations.