I would limit it to the inside face of the block, the distribution would still likely be 45 but as you say it’s are is limited due to the depth. But I don’t agree with the load distribution for the lintel since the block thickness isn’t great enough and the load isn’t centered. A high likelihood...
When solid it wouldn’t really have lateral load but there would be residual load as a result of the direct placement of the fill behind the wall, unless you pour the retaining wall afterwards.
Draw a free body diagram of your moment frame and share.
You should always do a simple hand sketch when trying to figure things out and not be completely reliant on computer programs.
During placement: Short lifts, bracing, or deadman tie backs.
Post placement it should have really minimal with unconfined strength since it is solid depending on how far back you go with it.
Reason why they can’t remove?
If they are installing insulation follow shallow foundation design for frost protection
Is this heated or unheated space?
What is the function?
Would the compressible foam compress under dead load or is there a foundation load path that spans the area?