It’s better to be tight to the warm side as in Fig. 2a. You want the insulation to stop the heat at the closest to the source. http://www.aecb.net/PDFs/Impact_of_thermal_bypass.pdf
In Fig. 2b, notice the 300% loss as stated above the pictures. You would still get convective loops if there are any gaps between foam board/stud walls, as in Fig.1-(f). After installing foam board on top of the concrete lip next to the sill plate on the wall, run another foam board on/over the sill plate to touch the back of the new wall insulation to stop any gap there. I’d use Roxul rather the poorest performing fiberglass batt. Be sure to air seal the drywall (ADA), Info-401: Air Barriers
add a sill sealer under the new bottom plate (capillary/thermal break), seal the top of wall/joist bay against fire/air, and seal the rim joists with rigid foam board. Pressure-Treated Sill Plates and the Building Code | GreenBuildingAdvisor.com
Insulate Basement Rim Joists | The Family Handyman
And don’t ever side staple batt insulation for a convective loop.
Foam any wire/plumbing holes in either wall- top, sides or anywhere, that lets air travel through. Give me a day and I will post on your vapor barrier……. No time today.