Hotel room/bachelorette party who pays?

Typically, neither you or FH should be planning bachelorette/bachelor parties for yourselves at others' expense. There are so many posts on this forum about how that can go seriously wrong and result in a lot of drama. It would be perfectly fine for the two of you to invite everyone to be your guests the night before the wedding. Depending on how you think things might go and their typical tolerances for alcohol, some might suggest the night before the wedding isn't the best time for a big night of drinking, but you know your crowd best.

I would book the hotel room but maybe let them decide what they want to do and what they can pay for. Maybe you can sit with the ladies but would let them decide what they want to pay for.

If you can afford to get the hotel rooms, I'd pay for those. Then make other activities optional & list costs so people know. If I was invited to something like this, I'd probably venmo the bride anyway just to cover some of the room cost even if she didn't ask for it.

I had a destination wedding with my bachelorette party the Thursday before my Friday wedding and HIGHLY recommend spacing at least a day between partying and your big day. No one drank too much at mine, but we did party until 2 am and I would not have wanted the pressure of knowing my wedding was the next day! (We had a welcome party on Friday night that all guests were invited to.)

My MoH planned the day, but I paid the hotel—some of the girls opted to stay with their BFs/husbands who were their wedding dates, a couple stayed at the wedding hotel but about half stayed with me. I did want there to be a free option for the girls since I really appreciated them traveling for me. I know that's a different different from your situation, but I'd still pay for the hotel. Spa treatments/food can be on everyone individually since they can budget what they can afford to pay.

All the bachelorette parties I have been to have been on the premise that everyone pay an equal amount to cover themselves. I.e. $150 per person which covers X, Y, Z, on a take it or leave it basis (there is always someone who says 'oh well if I don't come to this part of the night can I pay less?').

In saying this, as this will be slightly different, I would agree with other posters that it needs to be spread out. Nonetheless, I would have a chat to everyone first and see how they feel about your idea. This way you can see who is able to commit (including financially) before booking in.

Agreed with the others; I would highly caution against this. Take it from my BIL; he got super drunk at his bachelor party (night before the wedding) and was sick their ENTIRE wedding day. He regrets it to this day (almost 10 years later). If you don't see that as an issue, then do you.

As for paying, if you're offering to have them stay with you, then you should pay for the room.