For example, mine $150 a door for net profit.

If they don’t vacate, give it maybe a week and start the eviction process.If you’re feeling generous you can give them some numbers or website for some shelters or non profits, but beyond that there’s not much you can do.Only other thing is maybe give them their deposit back, but if they owe you rent, I wouldn’t do that.Good luck

Another issue, are buy and hold investors really going to pay enough to make a flip profitable?      

The profit margins on the flips aren't as high as when I had the employees but my liability is way less.

That way, you can understand if yours is a seller's market and predict fluctuations in order to adjust your timing when listing your property (spoiler alert: we can't really predict the future, but we can certainly identify trends and be more prepared than others);2) Consider potential uses: Depending on the demand in your area, converting a 4-family into a 2-family or single family home before selling might translate into higher and more profitable offers.

Then if you don’t like it, you can sell the house and keep the profit....however, if you do like it, then you’ll have more than enough when you sell the home or refinance it with the bank to invest in your next property!

Those capex eat away at the profit quick.

Additionally, make certain that you disclose that you are a licensed agent, and I would highly recommend that you get something in writing from the seller, signed, stating that he understands you are not offering to represent him as an agent and are entering into the purchase contract with the intent of making a profit. 

You may want to partner up with someone in your area that has done commercial property and have them put it under their name and just split the profits? 

I have a friend who profited 6 figures/year from a downtown spot targeting just that for several yeas in a row.If you're ever interested in getting into the Nashville STR market let me know!