Although my initial thought was the table saw would be a good approach, upon reflection it may make more work than its worth. If you cut the block on a table saw, or with a circ saw and guide, you will probably cut the integral plastic parts, which hold the block from spreading. My original practice of cutting with a sawzall maybe was unclear.....you cut the foam between the ties to gain additional bearing.

The additional bearing does not have to be continuous, but rather provides for the additional bearing you want, with perhaps 1.5 to 2" spaces along the bearing Ledger area.. Although I have seen the details as shown, I see no reason for either a brick ledge style block nor a "reinforced" site made ledge, when only holding the tributary load of half the span for a given floor area. You could bring your top bar to the inside plane of the original concrete core, but stirrups and rebar for a floor is a waste of time!

Take the rim board out of the picture and move the SIP in that amount. If you have 1.5" of joist end over the concrete you should be OK. The part of the sill plate that extends over the foam will carry some of the load back to the concrete. You can expect roughly a 45° angle for the load that goes back to the concrete, i.e. if the sill plate is 1.5" thick, about 1.5" of wood extending past the concrete will be carrying load back to the concrete. This effectively gives you about 3" of joist bearing area which is plenty. Most joist hangers provide only 2" or 2.5" of bearing length.

Draw it up and give it the joist supplier and SIP supplier. They can give you a definitive answer as to whether it's acceptable or not.

You will probably need to use blocking at the joist ends. Ask your building inspector. Mostly they're needed to keep the joists from tipping while workers are walking on top of them before the subfloor gets fastened down. And, workers will be walking on them.

Yep can just pour the wall, install top plate. Continue upwards with SIP planing outside. Use hangers or ICF Connect to allow the floor system to hang inside the ICF walls. This eliminates the tricksy air infiltrating rim transition wood sandwich, and is how a lot of conventional construction is going as well.

It takes a little more head scratching to do it right and allow your plywood to plane from joists to top of ICF wall. Also plan ahead for getting utilities into your upper exterior walls, as there is now a jog that makes access somewhat unavailable.

I'd also lean to utilizing ICF to top plate, but some would say I'm biased.... And using top chord bearing open web joists is also easily worth the money when you start running utilities. Not just once we've been told by a homeowner that "next time we'd use those open web joists like you said"

And yes ICF COnnect seem to work well, they also have a retrofit brackets can be installed after the pour.
Check your proposed plenum sizes for HVAC, close spacing of joists will cause bulkeads in main long runs, so sometimes bigger TJI/BCI's spaced a little farther apart is good to mull over in the planning stages- The "ribs fit around the lungs...."

Kevin