I hope the island has lots of food and we are definitely going to be out of it in a month... then it is a month of vacation... otherwise, anyone I get stranded with should be capable and mentally strong ... else they will eat my head with tensions about how to get out of there!!!
I would want to be with SIL as she is very sweet and always talks about nice things and can entertain herself and others with stories and songs like me!!
I would want to be with BIL as his interests are varied and similar to mine, so we would have lots to talk about - only if we dont pull each other's hair to get at the limited icecreams available in lonely islands!!
I would want to be with MIL as I've never known her (she passed away before I got married!) and I would like to know all about my husband from a mother's point of view!!
I would want to be with FIL because if I'm not there, who will take care of him!! And he would tell me all about building the right kind of house in this lonely island!!!
So my answer is all of them separately for a month each (oh not together they all will be fighting with each other and I'll be acting the referee!!!)
Keep smiling

Harini