You can also take advantage of lower down payment loan products rather than going 20-25% down on a conventional investment loan. 

Cost Overruns: After the final payment, the contractor claimed there were additional costs of $60K.

I see you mentioned the BRRR method, here's a nice breakdown of it here on Bigger Pockets.   

These two methods seem to be the easiest path to 800+. 

An example, a small down payment initially, but the note has now seasoned for 60 months with on time payments documented by a third party servicer.

As mentioned elsewhere, breakeven on cash flow is not the same as break even for taxes.Let's make some assumptions:Rental income = $1000Mortgage payment = $400 - but $300 is interest and $100 is principalOther expenses (repairs, advertising, utilities, etc) = $600Depreciation = $250The above scenario creates a break even from a cash flow perspective, however the tax scenario looks like this:Rental income minus the mortgage interest (principal is not deductible) minus the other expenses minus depreciation looks like this:1000-300-600-250 = $150 LossIf your income is over $150,000, then you cannot deduct that loss, but you can roll it over to future years. 

Here are a couple of methods of pipe replacement that I am aware of you might be interested in looking at.https://www.youtube.com/watch?

Then get photos and get third party verification that everything was done right prior to making your final payment to the contractor.

The biggest advantage of using someone local to where you're buying is that they will understand taxes, insurance, and similar items very well when it comes to DTI/DSCR calculations and payment quotes, and they will likely have a local network of service providers for ancillary services (survey, inspections, etc).

Sorry for the questions just curious about your method since it seems different than most.