2-3. Generate a new fallback list in 2019-2020 and backport it to all supported Tor versions
Here are the instructions for running a rebuild: https://trac.torproject.org/projects/tor/wiki/doc/UpdatingFallbackDirectoryMirrors
This ticket covers steps 2 and 3.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information