I would agree then. Here, the footing would be below frost, but it never hurts to add a "wing" of insulation to move it out from the footer.

As said before, To protect the outside insulation - Move your horizontal purlin's to the outside and use treated plywood. Then hang heavy plastic or ice and water shield down over it. They make some other heavy liner material, but its more expensive. You then can have a continuous sealed wall from under ground to top.

I would never consider Plastic Bubble as insulation. It's has virtually no insulation value when the concrete crushes it. If ridged foam or even the white Styrofoam insulation, rated for under concrete floors is used, it will not crush. Seen lots of it from a demo project of a repair shop and it wasn't crushed (heavy construction equipment, off road trucks and gravel trucks.  Under slab insulation on the whole building floor keeps heat from creating a temper zone under the slab down in the dirt. I don't believe in "heat sinks". Most of the new energy studies show it's not the way to go now a days. Your on the right path to a good efficient building for your area.