It's a total WIP right now. I have no manifests atm except what I have on the TeamWin organization and using aosp10. Also I have a couple of patches on gerrit.twrp.me for review. I can post my personal manifest later.
I am not affiliated with the minimal repositories and am not using them. You will have to talk to their members for status updates.
Thank your hard work with TWRP @bigbiff.
I'm trying to build the TWRP for pixel4a refer to your github repository.
I use aosp10 manifest and TeamWin's android_bootable_recovery repository.
I don't know how to make TWRP for pixel device.
It doesn't have recovery partition, so make bootimage OK?