Security Deposit in our case is one month's rent: $2,000Upon hearing our breach-of-contract request, the PM stated, "We are holding you responsible for the full term of the lease including and not limited to all rents , collections fees, broker fees , legal fees and any fees associated with the breach of your agreement.   

I'm not an expert on credit, but I would like to know if it is possible for a group of individuals to leverage their credit collectively as a group without having to start an LLC etc?

Have any fees collected at closing by whatever legitimate title/escrow company is handling your closing. 

This person did leave peaceably, but I did give them a couple short extensions on the time frame.

In other words, you're either collecting extra money from people who were going to do you right anyway or not collecting anything that will matter based on the repairs you will make later. 

I don't collect security deposits because of the major headaches surrounding their handling in Mass, FWIW. 

The assumption is banks want to collect monthly interest payments rather than call the loan.

OR, do I sell now, collect the 2-300k and run for the hills, all while losing a place that I will probably never have the chance to own again.

Now you need to start preparing for marketing, showing, screening software and processes, selecting a tenant, Fair Housing, emotional support animals, collecting a deposit, disparate impact, local and state housing laws, Section 8, your lease agreement, late rent, unpaid rent, partial rent, bounced checks, etc.No worries!

Didn't want too, but still cleared $20k profit and collected rent for 7 years.