For example using AirBnB services?

That's why buyer hire inspection services to complete their due diligence before closing.

Is your loan modification done through your mortgage servicing company or handled by the BK attorney?

If you're going to do this for the long-term, it's worth talking to a real estate lawyer and spending a few bucks to get it done properly until you know the procedure.   

Your willingness to bring something to the table by being of service. 

Are there online legal sites/apps that you can pay for this type of service?

A local real estate attorney can draft you a note and a security instrument (deed of trust, etc) for this lending arrangement.It would be good to have a loan servicing company handle calculating/collecting payment for a small fee (like how property management companies manage your rentals for a small fee).

I am specifically looking for companies with a proven track record of transparency and competitiveness in their fee structures and excellent customer service.

They will get a 1099 for the deficiency; in the case of a deed in lieu it's generally the servicers FMV - payoff.

From this you need to take your debt service (1500 - 1700/mth) and set-aside a reserve for Emergencies/CAPEx ($300 - $600/mth).