Pacvii Easiest way to do this is have your sis book the points (I prefer online as much faster). She can put your daughters info in there and note she's a guest not the member. This only let's Disney know that your daughter can't do certain things to the reservation that a member can it's no biggie.
And as far as getting room next to you it's never guaranteed even if you had booked both rooms. What my gf and I did is we noted at checkin we wanted to be close and they had us 2 rooms apart on the same floor. It wasn't a huge deal to us to be right next door.