can we have an emulator sub category for each category ?

You can make emulators appear on the leaderboards if you click Filter > Emulators > Shown. But as far as I remember there was a discussion on "do we not hide them anymore since there is Wii U VC which is faster ?", but I don't know the outcome of this conversation. Emulators are hidden by default because faster than most platforms.

The decision was actually positive on that matter, and visible still on the TMC discord. The changes have yet to be made on the leaderboards though.