The rehearsal dinner is the calm before the wedding storm, a chance to actually talk to your guests before the main event becomes a blur. Picking a Friday or Sunday instead of a Saturday night can knock a significant chunk off the venue minimums and room fees.
You need to confirm the headcount early to avoid paying for empty chairs. Once you have a firm guest list and a date, you can look at your cash flow to cover the $3200 average cost without scrambling.
This 0% intro period is a deadline, not free money. If you have a balance left over after 15 months, the card company will start charging interest on whatever is still sitting there.