Your plans sound sensible. I don’t think it’s common to do the MR, Muir, and back down the MR, but it works really well. Camping at UBSL is fine, but I prefer to camp at Iceberg Lake.
Middle Palisade, Muir, the MR, and the East Ridge on Russell are all classic routes, and they are roughly equal in difficulty. The MR is technically the easiest. Russell doesn’t require more skill, but it has more exposure. Whatever gear you brought for Middle Palisade (if any) is probably right for this trip.
You can get better route descriptions than I can give at summitpost.org or R.J. Secor’s book.
