Cool to see it worked out before it would've been revealed in the strategy guides. Here's the tweet for posterity hinting at Everstone + Destiny Knot + Mirror Herb being breeding items. If the egg moves all save into the Legends-style move list that'll be pretty convenient to set up full mons with.
Sadly, neither Roost nor Rapid Spin are on my Quaquaval's relearn list, so I guess that's still an advantage breeding the moves onto a mon has lol