We have a 1925 colonial in New England (Zone 5), and we had cellulose blown in most of the walls when we moved in. In one small bedroom, they ran into vermiculite in the wall, so stopped. That room has always been hotter/colder than the rest of the house, and no matter what we do with the balance on our forced air system, it wasn’t comfortable. We recently gutted and removed the vermiculite, so I’m now deciding how to insulate the walls. 

Walls are 2×4 construction, but it is framing i’ve never seen where there are tons of bays because each wall has 2 cross members (see pics), I’m debating between cut and cobble of polyiso boards (lots of work for me) and closed cell sprayfoam to maximize R-value in a 3.5″ wall. Is one going to be better than the other? Do I have to worry about the foil face in the middle of the wall if I stack 2″and 1.5″ (if I can – might have to just be 2″ and 1″ for 3″ total so I don’t touch the drywall). Total insulated area is ~180sqft.

So my questions are 
1. Which insulation option is better?
2. If I do foam boards, can I shove a full 3.5″ depth in there and still drywall? Is this even worth it vs 3″, and do I have to worry about the foil face?
3. If I do sprayfoam with a froth-pal etc, is low-GWP foam actually okay for the environment? Can I DIY this safely with a frothpak etc (I’m ok with a respirator and bunny suit).