I have a Cape Cod style home built in 1968 and since I have lived in the home my biggest issue with the house is the upstairs temperatures in the summer. Even with central air running the upstairs can get up to 80-85 degrees and in the winter it can get really cold. My house has a large downstairs where the master bedroom is and also another bedroom where my daughter's room is. My wife and I are expecting another child due in December so we've decided that we are going to move our first born upstairs but we want to make the room as comfortable as possible for her especially in the summer. We are nervous about putting her up there and it being uncomfortable The upstairs has 2 bedrooms and a bathroom and I have decided that I am going to completely gut both bedrooms down to the studs and re-insulate but I will do 1 bedroom at a time. The rooms need a makeover anyway so it is the perfect time to do it. This past winter, i gutted the bathroom re-insulated and is brand new so all that is left are the 2 bedrooms roughly 12x15ft in size each with 4ft kneewalls and the rest sloped ceiling. My question is, if I gut the rooms down to the studs and have someone come in and spray foam the complete sloped ceilings, knee walls and room ceilings as well as Air seal the rafters will it make a difference? Will the upstairs still get abnormally hot in the summer still? I have gable fans in the attic and I will be installing gable vents inside the kneewalls as well. Any recommendations are greatly appreciated.

I'm going to be in insulating the interior side of a milk Chute the milk Chute has plywood covering on the exterior and my question is if I should be putting vapor barrier and or XPS rogod foam and or just plain old batting on the interior before I cover up with drywall