Use closed cell spray foam on the entire wall as thick as you can afford with a 2” minimum.

Sounds like you're in the Canadian sunbelt, Climate Zone 5. Two inches would give you R-12, just 25% below the recommended minimum R Value for high performance homes from Building Science Corp.

Forget moisture-sensitive insulation such as fibreglass below grade. A vapour barrier is pointless and not required with ccspf.

Be aware that offgassing from ccspf will make your house uninhabitable for at least 24 hours after installation. For that reason, I've used it in new builds only. CCSPF must be covered by a thermal or ignition barrier.

Great information. Your're right and you know your stuff. I'm in eastern Ontario. thank you. The headers will be at 3.7in with a rocksol cover, so at or above code. The reasoning for the concrete walls is that most if not all condensation happens on the top 2ft of wall where it's coldest and a dewpoint is reached. The 2in of spray foam (Gynex) of that top 2ft of wall will provide the air barrier I seek, and should stop all condensation. Which would spray overlap with the black tacky tarp remaining on the wall below it. Then with a pink bat fiberglass at R14 covering over the entire wall from top to bottom, it will provide that addition R value at the top and also the bottom. So a great thermal barrier. Then an additional poly cover from top to bottom again to provide an additional vapor barrier. I have a extra fresh pink insulation to use so there's no extra cost. I just have to by a small roll of poly and tuck tape and some labor on my part to re-install.

Yes to 24 hours out of the house for full cure.

I'm doing this partial "flash and batt" because I think its the most cost effective way.

Is this reasoning good? Are their still risks to developing condensation behind walls? Should l get spray foam down to 3 feet?

I’m not sure what product the “black tacky tarp” is, but if it qualifies as a vapor barrier and you use a closed cell spray foam, which is a vapor retarder, then put poly over the whole thing, you would have a double vapor barrier. This would trap any moisture in the batt insulation. I would use a smart barrier product for the interior poly so moisture can move either way in your wall.

Poly over fg directly on the foundation wall is a surefire recipe for mold growth.

Either continue with the ccspf. You can then cover that with fg. Or attach XPS boards down to the floor, followed by fg (better yet, rockwool). All of it must then be covered with an ignition barrier.

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Last basement I finished on a new build was 2" ccspf top to bottom followed by drywall on framing.

For others, I put 2" XPS on the wall followed by fg and drywall. The inspector required poly; Building Science Corp.'s Dr. Lstiburek says it's not necessary--but it doesn't compromise efficiency.

CCSPF was the fastest and tightest system. Pricey though.