i have 4 STRs that i use professional PM, 2 of the STRs, after expenses including PM, are not outproducing my LTRs.For optimal ROI in this market requires a value add and quick, at least partial, exit.

Google can be a great resource......................

Construction is mainly CMU, Concrete, and Steel (at least for my projects), and there is a bottle neck of those resources as only few supply the area.

It keeps things professional while giving you room to grow your expertise.I admire your perspective on keeping your parents’ resources separate from your own—it’s smart to want to succeed on your own terms.

Here are some great resources for you to check out: The Book on Estimating Rehab Costs https://www.biggerpockets.com/forums/12/topics/862964-wholes...Wholesaling Calculatorhttps://www.biggerpockets.com/blog/rookie-241?

Odd's are given the scale of it all there will be some level of general cleanup resources made available for private properties.

Is that available to scale up and if there are investors,  resources to manage that side if the business.I imagine a $60M/year Lending business will need systems in place and more than 1 extra person.

So, these guys are not selling a pipe dream, I know that they did it with their own limited resources.

Sounds like you've found a reliable resource for SBLOC, but what you are describing almost sounds like preferred equity as well. 

The cons as i see it include loosing the 2 of 5 year cap gain exception, typically not an ideal rental because the emphasis at purchase was buying a good home for your family and not a rental with optimal return (my ex-home consistently has the lowest cash flow for equity in my RE portfolio), not disconnected enough from the property causes addition angst on damage and may result in over improvement.