On the floor your basic approach is solid- use tongue & groove plywood over the XPS, and anchor it to the slab with TapCons to avoid "leaf curl" or "potato chipping" warpage lifting at the edges or big waves. If that's going to be an issue for your floor sealer, skip the poly, use specially formulated foam-board construction adhesive to bond the foam to the slab, and the plywood to the foam- it'll stay in place without the TapCons, and the inch of XPS is sufficiently vapor retardent to protect the plywood & rug underlayment from any ground moisture wicking. If you want to save a coupla bucks, use Type-II (1.5lb density) or Type-IX (2lb density) EPS instead of XPS- it'll all have the same R value after 50 years anyway- the XPS loses most of it's (envirnomentally damaging) HFC134a blowing agent that gives it the higher R/inch in that time frame and the extra R0.8 isn't going to be a significant performance improvement at Louisville's 56-58F subsoil temp. R4.2 (an inch of 1.5lb EPS) is plenty for dew point control. Stagger the seams of the plywood with those of the foam by at least 8" to avoid rockering-compression issues along the foam seams.
The wall plan needs revision though. Ideally you'd put at least 1-2" of EPS (cheaper than XPS, and with far lower environmental footprint than XPS) against the wall-poly, snug up the studs to the wall-foam, and insulate the studwall with UNFACED rock wool (preferred, on multiple grounds) or fiberglass (still OK) batts. That way the stud edges and foam/fiber interface stay above the wintertime dew point of the interior air to keep condensation under control, the wood can always dry toward the conditioned space interior, and there are no thermal bypass air-movement cavities between the insulation & foundation. Putting the bottom plate of the studwall on the projecting lip is fine- put an inch of foam under it as a thermal & capillary break against ground water wicking and you'll have no worries.
In a Louisville climate you can use open cell foam to insulate and air-seal the band joist & foundation sill to your layer of wall-foam and the top of the studwall. It not only air-seals better, it's a far better R/$ proposition than closed cell, and uses much less environmentally damaging blowing agent (water, instead of HFC245fa ) to boot.