Looks like I might have room for about three more Sims. There are 16 Sims submitted thus far. I'll be placing a few of them in my SimSelf's household (but won't control them, except the caterers and mixologists) and the rest will be invited. I think I'll have @CathyTea's SimSelf and @AdamsEve1231's Bright Sisters be the caterers (Holly will also take photos) and @VanPelt81's Sims as the mixologists for the evening.
So far, only @friendsfan367, @TheAemaSimming and @SoulGal7 still need to submit. If they've submitted, I'll have enough Sims.