I decided to buy the property from my grandfather using a gift of equity, which allowed me to take over ownership without having to come up with the full down payment and pay for the tax lien and his closing costs.

When you said you had some money saved up, I was thinking that meant you would have enough for a down payment on an FHA loan.

Seller financing: Note for $1,350,000.00  - 7% amortized over 30 years with balloon payment after 7 years, interest only. ( I am trying to get the first year at 6% to stabilize then go to 7% remaining 6 years)Property Condition: Above average.

With inventory expanding, it feels like there could be opportunities to secure deals, especially if the right cash flow potential is there. 

all materials, all labor costs to others, Not you, utilities, interest payments, permits, licenses, auto/truck expenses, tools needed are all deductable. 

Maybe if you had a good, secure location to store things you could pre-order stuff you think you might need for your next project(s) and stockpile it.

I’ve done some research and have found that some banks will allow the seller finance portion from the seller to go towards the down payment of the loan, is that true?

I know there's seller finance and "B" lender that are good for the short term, but if a balloon payment is due say in 5 years, there's no guarantee that my DTI would be in a better place then I'd be stuck without funding. 

Don't change jobs or income yet.Once you do and you think you can manage the payments based on your new income, maybe once you get the rooms rented.Then if you want to switch there are plenty of opportunities. 

Neal and Jean-Marc were supposed to secure construction funds.