Now he uses property managers and I would bet dollars to donuts those professionals aren't offering cash for keys.I have 15 years experience managing 400 rentals and I have never offered cash for keys.

Operating Agreement: This document should outline each partner’s investment, share of profits/losses, decision-making authority, and exit strategy.

Some are, some aren't. 

Fundamentally these two issues aren't connected.1.

Since the tenant has a rental agreement nobody else has authority to give anyone else rights to occupy the property pending the result of the eviction.

Quote from @Tanya Maslach: Thanks so much @Greg Weik  - we aren't looking for  a house-hack manager.We are looking for Mid term rental management.

I don't think you can raise the rent by installing it because most guests aren't going to be using it anyways and it will prevent guests from booking potentially because your price is higher than others.II say all this as someone who drives an electric vehicle. 

Is being a section 8 landlord there doable, or is the housing authority and the city a hinderance to deal with?

You aren't getting any payments, but you do have ownership and any equity upside.Some markets do not produce any chas flow/yield.  

They're definitely an appealing option, especially when long-term rentals aren't cash flowing as well.