We’re in the process of renovating part of a late 19th century carriage house in Philadelphia.  The stem walls are Wissahickon Schist and change to triple wythe brick about 3o” above grade.  The floor system is actually positioned about 48″ above grade creating a crawl space which is technically unvented(no intentional openings, but very drafty so in essence, vented in some way) with a concrete floor for about 90% of the area and a small section that is gravel. The building has no insulation in the exterior walls or roof and approximately 8″ of blown in cellulose in the attic. We are renovating half the first floor and have performed demo on the interior exposing 3 of the exterior all the way to the brick.
Here’s my question: I’d like to take the opportunity while the brick is exposed to do whatever air sealing and insulating we can before constructing new walls inboard of the brick. I’m considering closed cell spray foam as a way of achieving both air sealing and insulating (though the off-gassing seems to be a potential issue)  or a fluid applied sealer with a dimple mat, smart vapor barrier and rockwool inboard of that. I understand that there can be an issue with the moisture condensing inside of the beam pockets and rotting the ends of the beams and the rough openings for the windows have wood lintels on the inside coarse of brick which I fear could rot if encapsulated in the foam. The floor system is comprised of solid 3×12 joists pocketed into the brick every 16″ or so. I’ve been told insulating on the exterior would be best, but this isn’t an option as we are preserving the historic look of the building.  I’ve also read that uncoupling the beams from the masonry is an option, but I’m not convinced that the logistics of this are feasible for us. How concerned should I be about the potential for wood in the masonry to remain damp and rotting, and also how concerned should I be about the off-gassing of the spray foam considering that the home is currently occupied?
I’ve attached 2 images of the wall assembly and detailing features I’m considering in addition to the above questions, what would be the main purpose of choosing the detail that includes the liquid applied weather barrier over the one without?
Thanks,
Michael