layers) and essentially did a full gut rehab, including correcting some structural issues caused by an attempted "fix" of a bad tub surround in the shower.

Once you remove the shingles, theres a good chance you might need a new layer of OSB.

when my property insurance company suddenly outright rejected coverage because of knob-and-tube wiring and multiple layers of roofing and deteriorated chimney.  

I know this an epic debate for investors but my personal opinion leans towards having a license especially if you in the wholesale business.... puts a layer of disclosure on top of course but allows you to give the property owners some options. 1) "I have investors who are looking for properties like yours that can pay cash and close quickly to solve your problem Mr Seller" or 2) "Just need to sell but don't have an urgent time constraint you say?

Using "the cash flow to pay down their respective mortgages" will be VERY slow in the case of Turnkeys, especially because you're already up for an extra layer of costs. 

Things where deferred maintenance is 3 to 5 layers of shingles, bad furnaces- you name it.  

We want to buy the house with them as the owner, then put it in a land trust immediately so that when the inevitable occurs, we acquire the property, and so there is at least one layer of asset protection. 

If it comes to eviction having a co-signer is another layer to contend with in the process.  

It'd be nice if i could remove a layer of variables from the purchasing process.Thanks!

It can be challenging enough managing rentals in your same town then add the layer of being an absentee landlord to the mix requires careful planning.