This is awesome work! I hope you can start the MBF soon.
One minor comment:
* 862 failures - Of these 217 failed with an error related to this change - The remaining failed for other reasons (including running out of memory on the host, etc.)
I'd like to look at those "remaining". Can you put the list somewere? When I test for packages which fail if "some special condition is met" (for example, make --shuffle) I usually try to do two groups: Packages which fail with the condition and packages which would fail anyway, and I try to be sure in which group each package is, so maybe I could try to fill the missing gaps here. Thanks.