Thank you for being open minded.
> Reference System
I would suggest piggy backing off another platform for now so that you can get the legwork out of the way and focus on the more unique/cool stuff. Tons of people have multiple listing across AirBnB, Couchsurfing, etc, so I don't see any kind of argument against adding yours into the mix. On your side, this would entail forcing all hosts to link to at least one verified platform and making sure that all their contact info matches what is available in that link. You wouldn't want someone to misrepresent themselves by saying "hey this is my cool place in SF!" and having an email address with a suffix of .co.kp
> Request Management
Same idea as above. Implementing internal messaging is unfun and feature wise would probably not compare to the more established platforms. So, for now, allow hosts to suggest their preferred method of communication[1]. You'll probably won't be able to capture the conversations and, in my mind, that's fine at the starting gate. For now it's all about getting a good liquidity, i.e. guest lookings vs hosts accepting. Regardless of if this is intended to make a profit: guests want lots of open places/people, and hosts don't want to be overwhelmed.
The trick is to make sure your platform has a value-add ( so guests + hosts clearly realize it's helping them!), I'd recommend suggesting to hosts to tell prospective guests to write things like "Yo, I saw your thingamajig on HackerCouch!"[2]
> Couchsurfing trademark issues.
Is there another fun word that conveys what you want out of this platform? It's definitely not worth tangling with Couchsurfing the company.
[1] Chats like slack or IRC are generally not a good medium for requests/pre-hosting conversations, in my opinion. Hosts don't like feeling pressured to respond in the way a chat medium kinda-sorta-implies you should, and requests can tend to be on the longer side. Note: longer messages like emails are pretty always the case for any dialogue with a trust deficit; chats work much better once the two parties have gotten to know each other/don't have to carefully formulate their words.
[2] I have strong feelings about the way requests & references work, in ways that may not be scalable. So I'll try not to push my opinion too hard.