So I've scoured the internet and there's no confirmed flavor from Disney and all of the blogs/Disneyesque news sites list different flavors. I'll have to ask before I buy because I don't want to buy something that's just going to be thrown away if I don't like the flavor.
See, the grape sounds gross to me!

Blueberry lemon pound cake sounds awesome, I'll ask a cast member before I buy for sure. Otherwise they might as well rename it Jelly Belly popcorn, good luck guessing the flavor.