Long terms on commercial properties (5+ units) that are stabilized (typically > 85% occupied ) tend to be based on the property itself, not your personal guarantee.

After the 90 days are up, the flipper can now sell to an FHA/USDA buyer, but if the flipper sells it for DOUBLE of what they paid, then the flipper will have to pay for a 2nd appraisal to go along with the first appraisal that the buyer typically pays for.  

30-60k per door on your typical value add class c

Assuming you would buy the foreclosures from the county auction, foreclosures are typically harder to finance.    

Typical breakout is usually 60/40 but depends on the property.

Depending on size of lot and # of structures and impervious surface these typically are not cheap

How long is the typical due diligence on a property like this?

Typically it breaks in hottest or coldest day of the year and that’s when you will pay a premium price to get it replace or fixed.Personally I would not want to install a refurbished HVAC system, I think you’re better off w new installation and not have to worry about it for a long time.Typically when I purchase a unit and I know HVAC system is over 15 yo I know that sooner rather than later I will have to replace it and I plan for it..

"Site control" (sourcing a new deal under contract) is typically one leg of the stool--the others are capital and experience (such as rehab & project management, etc.). 

I currently work as an engineer and plan on using income from my day job to finance downpayments for rental investments.I am interested in out of state investing as the cost to enter my local market (SF Bay Area) is a lot higher than I can afford and don't typically provide cash flow.