You still have the cost of lease renewals, but that's minimal when compared to the cost of turnover.  

If a person has RCV or ACV policy makes a huge difference, than question of what coverage level people had and if they had policy add-on's that cover cost over-runs and all that fun stuff, not to mention contents. 

Well anyone can write anything into a contract, but whether it is legal and enforceable is for the courts to decide...It is State law here that a contractor must call 811 or they are liable for the costs.

You need to know what things cost.

All else being equal, lower mortgage rates reduce the cost of ownership and, thereby, allow more people to afford to buy.

For your first BRRRR, plan for extra in your rehab budget—unexpected costs happen.

The cost shouldn’t be double what a duplex is, but should likely be less per unit.

From there I accepted and negotiated to have the seller cover the cost of replacing the roof.

Combined that can cost $50k+ which they may not want to pay nor their is the possibility they would not they pass the DD report.Nothing wrong with raising money in this fashion (FB or online ads), many do it and are great sponsors. 

Having a real estate license, I would credit the commission payed out I would receive for being my own agent towards closing costs for the new property.