What you are describing is called adverse selection - you have a known issue and want to buy an insurance policy to fix your problem because that is less than what it would cost to have the work done and you pay directly to the trades. 

Its hard enough to find the "right" house to live in, but when you add factors like: foundation repair, new roof, new hvac, complete cosmetic over haul, it makes it that much more difficult.Certainly can be done, and not only that, you can find a house in Collin county off market cheaper that what you would pay retail.Its important to make sure you have a resource for properties, an investor friendly lender Ie.

With this setup, the buyer would still make the same monthly payments, but instead of stretching those payments over 30 years, they would need to pay off the remaining balance at the end of 5 years.

Some people say it’s 12 months minimum before you don’t have to pay back the grant while others say 24 months.

Cash-flow for us pays all the bills and funds our lifestyle.  

It depends if you have a lien on title already (a mortgage or hard money loan), but I would either do this as a hard money refinance or a DSCR cash-out refinance to pay for the reno. 

If that's what I would be getting from my sublessors (i.e.current tenants), how much rent should I pay the owner?

You typically have to pay per 30 days but I've seen that it's worth it as an extra protection for us landlords. 

The one deal I got will profit me enough to pay for the application for 2 years.

This year she ghosted me after paying her!