basement insulation on top half-frost line

Fiberglass is an air filter the same as Rocksul batts. They are both conductors and allow cold and warm to touch.Styrofoam has a true field R value but it is only as good as its smallest crack where the cold gets behind it. If you seal the styrofoam with the foam cans 100% you will be fine. I put a life time gaurantee on my work so i only trust spray foam and cellulose injected tight because of the perfect fit and density. They both have a hollow cell which creates is own vapor barrier. They have a true field R value. I hope this helps

Solid plan overall, and better thought-out than most DIY basement jobs I see. Skipping the poly over the batt is the right call — foam board there is already handling vapor control, so adding poly in front would trap moisture with nowhere to dry out. A couple of things I'd nail down first: what climate zone you're in, since that determines how thick the rigid foam needs to be to keep condensation from forming inside the wall rather than at the surface. Also worth checking that lower wall for any past dampness or water staining before you cover it — easy to miss now, a pain to find later. Two small details: code usually wants a thermal barrier (like drywall) over exposed rigid foam even behind framing, and put a sill gasket or PT lumber under your bottom plate so it's not sitting directly on the slab. Get those squared away and this is a good approach.