What brand ICF and what is advertised R-value? What is the insulation strategy for the poured walls and how much will that cost?

Nudura blocks with an advertised R of around 24. The poured walls would get blanket insulation which would cost around 1K if I do the labor

You really shouldn't use blanket insulation on a poured basement wall. Too much chance for damp insualtion and mold. Go to greenbuildingadvisor.com for recommendations. Keep in mind that all of the ICF foam has to be covered on the inside with a thermal barrier and you'll have a more expensive dampproofing on the outside. You'll also have to protect it where it's exposed above grade. I like ICF but that's a pretty big spread.

With the formwork issues, I’d do ICF and call it good.

To compare equally, consider the poured wall including the cost of insulating and any framing for that insulating. Examine the schedule differences.

$6k to me seems reasonable but of course size matters. Is the walkout portion included in the ICF quote or is that just a conventionally framed wall?

What is the performance of the rest of the house? R value etc.

To get R-24 on a poured concrete wall correctly involves losing some interior space - like 6 inches probably. Blanket insulation - what do you mean by that?