Should I buy six concert tickets before everyone has transferred their share?

The group chat had four thumbs-up reactions and one unread message when the ticket queue opened. I needed to choose six seats together or release them.

There are six of us including me. Tickets are $80 each, and I could put up the $480 today without missing a bill. I've already received $160 from two friends. Two others reacted but haven't sent anything; the last hasn't replied. We'd discussed this concert, but nobody agreed that I would commit their money before hearing back.

The booking screen says ordinary change-of-mind refunds aren't available. I don't know whether we'd find another friend to take an unwanted ticket. My partner says the silent friend will probably be delighted I got seats. I think that's a generous guess to make with my money.

Would you book only for people who've explicitly confirmed and paid, take the chance on the whole group, or let this set of seats go? I enjoy organising things, but I don't want that role to include buying an $80 surprise for someone who hasn't answered.