@Patrick Menefee it’s touch on those situations, but here are a few suggestions;Cameras as you have stated, security company, guard dogs (there are companies that do this for hire), give a cop free rent for one of the units while under rehab, let one of the contractors stay while rehab is being performed. 

Consult your local planning board and hire an engineer.

I would 100% hire a property manager though, I can only imagine the headaches involved with dealing with that many low income units at one time.

I think, unfortunately, your friend made some very critical mistakes that are going to cost him time and money.Here's what I see as the steps to unraveling these egregious errors:(1) Hire an attorney whom specializes in landlord/tenant law(2) Wait for the eviction moratorium in NYS to end (patience will be required here, as we're at 16 months and counting)(3) Under your attorney's advice, carry out an action against this freeloading occupant as a "licensee"  (I think it's called section 425?

Meaning should I also do the majority of the renovations with my small crew and only hire sub contractors as needed.

I feel comfortable with this because I know I can always fall back on serving if I need to (there are a few restaurants around here that are always hiring, and that's the work I've done for years that allowed me to save up for this house).

Seller will need to hire an agent, preferably one with short sale experience, and go through the short sale process with the bank and list the property for sale.

Likewise, same question applies to renting out a vacant unit (obviously some amount of cleaning goes on here but do you hire it out flat rate, hourly, ect.) 

If not, I can hire a realtor for 1 month rent to lease out (2k is what I am hoping to receive/month).  

Three years ago he hired a syndication coach and now he has over $100 million in multifamily deals.