If you split the profit 3 ways (after all the fees involved with selling), would you have enough to buy a new place, make any necessary repairs, and have some money as a buffer to pay the mortgage in case you can't get a tenant right away or something big breaks?

When we buy our units, we make sure that he have buffer in case the market were to drop.

The good thing is currently with the cash flow potential so high, we have a very nice buffer, so even if we are REALLY struggling, we are still cash flowing as much or more than LTR would for the same property. 

Plus, when we first got into investment property, we bought several townhouses thinking cheaper than detached, better cash flow, but found we had huge issues with the adjacent units (can't control who the other guy rents to), so we decided single family detached just provides a buffer from the guy next door.

Profit margins of around ~23k, and still have the house that isn’t maxed on its current market size for safety margins of market buffering or easier forced equity to stay afloat.

(d) For base buffering encroachment lands acquired through a fee simple or less-than-fee simple acquisition under s. 288.980(2)(b).(2) An easement described in subsection (1) and the rights of the owner of the easement shall survive and be enforceable after the execution, delivery, and recording of a tax deed, a master’s deed, or a clerk’s certificate of title pursuant to foreclosure of a tax deed, tax certificate, or tax lien, to the same extent as though the land had been conveyed by voluntary deed.

If you are careful, you try to over-budget with a buffer, and have a detailed scope going in, you have an opportunity to not only get the renovations done and create some equity but you eventually will be able to find opportunities to make the rehabs more efficient and create another source of leverage for yourself.

Then those activities you listed become the safety buffer that you can lose in an argument with the IRS and still have 750 hrs.Also, there's a controversial issue about an election to aggregate.

Pretty overkill, but gives enough of a buffer I don't think we would need to worry.I really think I could make do with less, however these amounts would make me feel comfortable leaving my full time job if my primary house wasn't paid off. 

Create a buffer.