When I removed the things marked as supporting "Chromium build inside SDK" with change:

https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl-demo/+/24322

it turns out that I missed that that dropped the lua, libafb-helpers, and libappcontroller staticdev packages needed to build some (non-Chromium) widgets.  When I tested the SDK pre-dunfell merge, I used a couple of apps that didn't need them, unfortunately.  I'll upload changes shortly to make the base TOOLCHAIN_HOST_TASK and TOOLCHAIN_TARGET_TASK additions done in agl-image-minimal-crosssdk into an include file so they can be sourced from one central place.