If I'm reading right, that'd be great. And they ususally let you get most non-legendery if not all sometime in the gen without having to trade with older games.
It'd be kickass if ORAS kept X/Y's generous IV legendrey system, would love to catch me some awesome Palkia.
I do think Heatran and Regigigas would easily fit into Hoenn. There's Mt Chimney which would make far too much sense to house Heatran, probably post-game. I'd theroise given it's strong connection to the other Regis, Regigigas may be actually in the native Hoenn dex.