Hey man. Glad you want to contribute!
FIRST QUESTIONS' ANSWER:
Just put as much information as you do know.
http://www.walking-barefoot.com has the dates for many of the shows as well, so if you know the era and location you can get the date, etc... You should know the tracklist if you can hear the songs... other users can help you figure it out if there are some songs you don't know. If the bootleg is incomplete, just post the ones that you have and include a note that says it is incomplete. If you don't know ANYTHING about the bootleg, the least you could put would be:
Live Recordings - 2001-2002 era (guess the era based on the setlist/album)
or
Live Performance - 2001-2002 era (for a whole set that you don't know info for... you should at least have SOME info though, right?)
...or... just post the single song: Ex: Sweet Child Of Mine - Acoustic. Put a subject you see fit and if it sucks, I'll edit it =p
SECOND QUESTION's ANSWER:
Yes, you can upload Ash covering other artist's songs! In fact, it is encouraged! =) The only one's that you cannot upload are ones that have been released b-sides or album tracks... for example you CANNOT post Ash's studio cover of Nirvana's Blew or Mudhoney's Who You Driving Now? Most of this site's media will be live or session performances. Maybe I will go ahead and upload all of the b-sides I see as OK to upload when I get home...
Hope that helped! I know it was lengthy, but I wanted to give you a good answer!