Cellulose touching roof deck

Hi all, I have cold kitchen in my 1909 row home in philly. It's been built above a converted garage so that doesn't help, but additionally, it has two exterior brick walls. The prior owner did a remodel by laying 2x4s flat against the plaster and lathe, so I'm gutting the exterior walls as well as the pulling the floor up. With the floor, I'm thinking of going to joists, and insulating from above. Then new subfloor, electric floor heater, and then tile on top. The walls are two layers of brick with a stucco finish on the exterior. The interior of cement brick, and the exterior row is a red brick. If I do 1 or 2 inches of rigid foam on the interior, will I create a Vapor issue? Also, do I apply the foam over the entire surface, then try and fasten the drywall over top of it? Do i use screws and try and get into the brick? Do I glue it? Do I put firing strips on the brick? Do I put firing strips on the foam? There are tons more qs. So beware, if you respond, I might just ask a follow up;)

I have a two floor home. A few years back I added the second floor and when I did that I installed r30 insulation under the second floor with vapor barrier against the second floor with radiant floor heat above. I never removed my first floor ceiling r19 vapor barrier thinking I should not have issues between the two floors. Others agreed this to be the case. I am now doing some renovations to my first floor and have access to about 60 to 65% of the first floor ceiling insulation. Would I be better off leaving the vapor barrier or removing it knowing if i removed it there still will be a double vapor barrier over 35 to 40% of the first floor. Thanks Gary