Bonus would be refacing the cabinets if the pricing makes senseI priced out part of the job with HD, windows were somewhat reasonable at $8500 but I was surprised by the cabinet refacing -- Just short of $20k.

FHA is currently streamlining everyone through short sales.

Both are irrelevant. 5+ years ago it was the 2% rule and I have been hearing it in REI meetups since shortly after the Great Recession (at least since 2012).  

The strategy involves using the HELOC for a flip to generate fast cash, reinvesting profits into long-term rentals, or exploring alternative ventures like short-term rentals or partnerships.

The two big risks I see in your assumptions is: lease up time (6 months, generally, sounds short).  

Some extend their contracts and will want to extend their leases, others may have their contracts cut short abruptly.

Assuming that you're buying a turnkey property, the delayed purchase is meant to be for borrowers who have very short timelines to be able to close, have the money to purchase up front, but still want to leverage their cash.

We are not seeing nearly as generous for a 12 month leaseback, I have one right now, I either get term of LTV, but not both for a short term SLB.Re-tenanting is your biggest risk, what does your balance sheet look like if you have to hold it vacant for 12 months?

I have a unique property, it's a 4 bedroom home with a lower level having a few small commercial offices and then there's a 22x35 oversized garage.  I'm having trouble finding a tenant that I feel comfortable leasing ...

However, if I feel they are coming up short, I'll reach out.