NBR- Bridal/Lingerie shower advice?

I know this may be a better question for "the Knot" boards but I figure many of you may know better what to do or have some ideas and since I don't frequent the Knot...

 So a couple months ago I offered to throw my future sister-in-law a bridal shower for our family and her friends here in Chicago. She informed me that she wanted a lingerie shower with just her friends rather than a traditional shower with family and friends. Wanting to be nice and help establish a relationship with her I agreed.

So we decided on a date and she gave me a list of friends to invite, etc. Well, I just got the last of the RSVPs yesterday and it looks like only 4 out of the 13 friends she asked me to invite are coming! Now maybe it's just me but I'm thinking that some of the games or the overall feel of the shower just isn't going to work anymore.

With the shower being this coming weekend, I'm not quite sure what to do...How would you approach this situation? Should I maybe find a small restaurant/cafe for a luncheon and pay for everyone's meals since it's going to be so small rather than having the party at our place and making lunch? Not that my husband and I have money to do that but I want my future SIL to enjoy herself as well as all the others, but I'm having a hard time figuring out now how that's going to happen..especially since I don't know any of her college friends (I think they are all Sophs at Moody..)

 Any suggestions would be greatly appreciated..