If the hoa is foreclosing you probably also have taxes to pay and the first with default interest and late fees can be significant

Not sure of California, in Virginia, it might take 3 months of back and forth court visits before everyone is out.Maybe better to get everyone on the lease and assign clear, monetary fees in writing for violations.

If HOA fees, HOI Fees, and taxes haven't crumpled some it will.

It should be what it is now in which is the delinquent amount plus any additional  fees accumulated.   

Charge a monthly fee, have multiple students at once all use zoom meetings, or even sell a course for a certain amount of money.DO NOT continue to tell people they will make $500k and that it cost $15K+ to do so. 

buying and selling is also expensive - fees, fees, fees.not trying to be discouraging, just realistic. 

Who pays servicing fees?

You are making enough income to bring a check with you if you can't sell for what you owe + any fees.

Points and fees like a traditional bank?

The scenario would be using a flat fee listing service where there is no agent.