3) In my private discussions with David Marchand, he expressed interest in getting the git log history. The current review process will not help in this regard. Is this a must? If yes, are there any known methods to do this?

The git docs point to https://github.com/newren/git-filter-repo/, since apparently git filter-branch is full of footguns. From there, I would follow an example from Ruby, https://gist.github.com/x-yuri/9890ab1079cf4357d6f269d073fd9731, which was merging two reasonably-sized tooling repos. Instead of using git merge, we would be using git rebase. I did it locally to try it out, and it does have to replay the ENTIRE git history of dts. This means whoever does it may want to grab a server and do the rebase in /run. This would also mean that we would have to bypass the mailing list, since sending out more than 32000 emails doesn't seem reasonable. Possibly just a patch with the script to run to do the rebase instead of putting all the patches on the mailing list?

Doing this would also probably mean all of our work would be in the DTS repo until we are ready to merge. That might make it harder to review changes to DTS in small parts.