simple answer; all of them. The first one she wants is the strawberry then she just goes down the list asking for each one(except for banana for some reason) also make sure to stock up on apples, cantaloupe, and watermelon, you'll need them for later.
Ask the fairy. If you don't know what I'm talking about, throw the gold dubloon you got from Shadow Curios into the fountain. If you don't HAVE the gold dubloon, sorry to say it, you're softlocked.
The last one you get is for the hotdog eating contest. You need to get to the highest weight level in the game to beat the last contest, so the sandwich is very much end game content. As for the rest, you need the vials for the bagel and the wagyu beef and the gold dabloon for the fairy, both are bought at the curios shop, and both the flavor enhancers and the High quality greens are locked behind Tiffany so you need to unlock the lab for them(Also one of Cici's endings result in Tiffany going away but don't worry, that doesn't stop you from doing Diane's stuff).
One thing I would like to note assuming your still working on the sequel, having the wings make you faster is not helpful. Generally in bullet hells, it's much more important that you can make small movements to slip between bullets so going faster only makes it harder to dodge.
If I could make a suggestion, you could make the wings unlock 'focus mode', a feature used in most bullet hell games that makes your hitbox visible and makes you move really slowly for easier dodging. Upgrading wings could increase the amount of time you can use focus mode.
Whenever I try to stream I just get this error message and trying to run it in browser just gives a message saying "no valid memory adaptors"