but not what communication protocol is actually being used.
http, https://gitweb.torproject.org/torspec.git/blob/HEAD:/dir-spec.txt
section 1 line 184 "All directory information is uploaded and downloaded with HTTP."
If you search through the document for http, you will find most of the uris and related info youre looking for.
tl;dr/no idea for the rest of your post.