Sounds like a great idea - I'd recommend checking out something like The Host Co if you haven't already.

If you're friend still need needs management/co-hosting I'm available to talk.

The direct booking site is totally up to the host!

I host an investing meet up and every 2-3 meetups someone comes that is in trouble with either living in or renting the non-conforming space.

I am a STR VA/Co-host looking for another client, preferrably Gulf Coast location. 

Or a host of other occupations that my medical condition precludes. 

Join some local Facebook groups for hosts, and some local FB groups just for local residents. 

As a host here in Florida i would always make sure to have an umbrella policy that covers personal liability if something happens.

For out-of-state STRs investors, is it normal for a cohost / property manager to insist on creating an OTA listing on their account to better streamline their systems? Seems like a potential issue if I stop working wi...

I lend money privately and would never consider this as it is dependent on things out of my control (permits, neighbors, you being a good host, rental demand etc) I sell a ton of STR that are in actual resort communities and have great amenities and they are all  competing for the same guests, I can't imagine that there is a need/demand for this type of unit.