https://barneswalker.com/seller-financing-restrictions-under-the-dodd-frank-act/ I understand Dodd-Frank more on how it applies to "traditional" lender financing, but if you have any specific questions I'd be glad to help.

In general for a traditional loan, it needs to be a complete and functional home absent safety hazards. 

If I can make it work, it would save me a substantial amount of taxes.I would then plan on taking those funds (profit from the flip) and either (a) investing it in other self directed eligible assets (RE, LLC interests, etc.) or (b) transferring it back to a traditional brokerage firm and to simply invest it in equities.  

Reason why there is no allotment for CapEx is because major items like roof, hvac, have >5 years life (or more).

If it's a mixed receipt where you bought some items for home use and some items for the flip, mark what those items are on the receipt.

I am considering making and offer on a personal residence and thought about giving two options: 1) traditional offer at a lower value 2) a land contract (seller financed) @2.5% with a 7 or 10 year balloon.

If you can't find a traditional bank that will lend to you, there are vacation rental loan companies.

I'm purchasing a duplex on a 30 year traditional mortgage.

I have been pre-approved through the traditional means (20-25% down) but I have been recently offered, by someone I trust, to borrow money from them using money they will pull out of a HELOC on their primary residence.

They also did a variance analysis for each line item in the P&L.