In northern virginia 1960’s masonry  building with wood joists:

Thinking about energy retrofitting my basement but am concerned about increasing the possibility of rotting wood joists:
The existing joists sit on a masonry shelf and are pocketed in with CMU on each side and probably the top. The ends of the joists are covered by the face brick on the outside. There is no air gap around the joist in the masonry pocket.  The masonry joints are in ok shape and there’s no evidence of leaking to the interior. the wall below this area is below-grade. It is CMU and looks like it was painted or had some Thoroseal applied.

I am thinking the following
1. parge the CMU with a lime-based coat to cut air infiltration through the CMU block.
2. caulk the joint between the wood and the parged CMU block to air seal [low modulus caulk[
3. cut and cobble 2″ or 3″ rigid insulation with sprayfoam at the perimeter. [i have access to plenty of XPS or poly-iso.]
4. drywall the ceiling in this location.
5. i don’t have immediate plans to insulate the below grade wall.

a. Will the SYP untreated joists be more likely to rot since more of end long grain can’t dry? I am not sure how much wicking i get with the end grain being buried in the masonry. No staining visible so there is not significant wetting-drying going on. 
b. is there advantage to a dedicated air barrier outboard of the insulation or is it just wasted effort since the rigid will perform as an air barrier anyway?
c. If I had thought of this question in the winter, then I would have done a thermal scan to see the temperature differentials.