Can a player pass priority after playing a reaction, and if both players pass, play another reaction before the first reaction resolves?

Ruling: No. When you play a reaction you hold priority, but if you pass priority and your opponent also passes, both players have passed sequentially and the top item on the chain resolves.

Sequence:

• Player plays a reaction and holds priority
• Player passes priority
• Opponent passes priority
• Top item on chain resolves (both players passed sequentially)
• After an item resolves, both players get priority again (whoever has the latest item on the chain gets priority first)
• Players can now respond to remaining items on the chain

Nuances:

• You can play multiple reactions while holding priority without passing
• After a reaction resolves, you can still play reactions to earlier items still on the chain