Hey,
Hm, well this would be my first co-op bundle so I'm not 100% sure, though having read the details on hosting a co-op bundle: https://itch.io/docs/creators/bundles
It says: 'Due to the complexity of distributing purchases across multiple sellers, all purchases of co-op bundles go through itch.io’s payout system. Prices are done in USD and VAT will automatically be added if necessary.' and when you click on the link for itch.io's payout system it take me to the normal payout page that I use, and I use paypal. So maybe it would be fine.
Thinking about it, I would guess the majority of users use paypal, so it would make sense for it to work that way.