Max began preparing to have a massive influx of visitors just after everyone started to get settled in, but that wasn't something that he hadn't had practice with before.
The staff of Terminus had gone through this multiple times before, and the entire city that General Tennant had settled had suffered the same fate, so he knew that he could at least host a party, even if most of the ship wasn't entirely online and ready for regular business yet.
It would help the crew bond, so he began to make plans for a multiple-day event, having his crew party the night before the christening and then continue it through the day with the visitors present.
That should give them an idea of who was local and who wasn't, as well as provide them with a chance to interact with the Reavers at large. They were guaranteed to see a lot of them in the future, given the size of the ship and the facilities that it boasted.