"As a side note an engineer looked at the hangers vs brick ledge on a project years ago and advised hangers are actually stronger for floor load than brick ledge. I assume this is because the brick ledge is designed to take a high vertical load (ie, brick stacked on top), while a floor load would impose a vertical load and a lateral load (due to floor deflection). Feel free to correct that assumption...."

That is precisely correct. And concrete is strong in compression, but is not strong in tension. Steel is strong in both compression and tension.

Hi Jessy,
There is good article regarding more insulation.
https://www.energyvanguard.com/blog/76941/The-Diminishing-Returns-of-Adding-More-Insulation
More insulation is always better but when I was building I did FoxBlock 8" in basement and 6" above ground. I did investigate Fox Block Energy Sticks, but the additional cost vs energy saving wasn't justifiable. I don't remember details but my saving per year was going to be under $100.00. BTW I'm in CT.
My house and basement is somewhat square 40x42 and basement is mostly in ground with exception of east wall. When my house shell was finished, open to the attic, no ceiling insulation, no drywall, no doors to the attached 2x6 stick garage, no doors to 2x6 stick bonus room above garage, no heat in the house, open eaves the basement never got below freezing. Mostly stayed around 40-45. On the cold days when I walked in the basement it felt significantly warmer vs upstairs.
When I did room by room heat loss calculations my 2 pane windows 36x56 rated at U-25 in room 15x12 with 2 outside walls these were loosing same amount of heat as all my walls. I think if you are willing to spent more money it may get you bigger bang to use this for windows, attic or floor insulation.
Congratulations on your build.
Jerry