Here’s some context: Property 1: >$100k in EquityValue: $325kDebt: $220k @ 2.88% (30-year fixed)Property 2: >$70k in EquityValue: $325kDebt: $252k @ 3.38% (30-year fixed)Extra considerations: - I have $15-20k liquid to use for any of these deals- My current job is relatively stable, but not high-payin- Current properties in TX, living in NY, looking to invest in Mid-West (crazy, I know)- No other debt obligations besides the two mortgagesUltimate goal/timeline: Though a bit ambitious, I’d love to build up the portfolio to 10-20 units in the next two yearsI understand that any/all replies aren't financial advice; all ideas welcome for information purposes. 

My main question is whether it makes more sense to go the seller financing route and pay off the principal in 8–10 years or stick with a standard 30-year loan.My thinking is that the tax deductions from a mortgage wouldn’t outweigh the potential equity I could gain over those 8–10 years.

Depending on your debt to income, you might have to sell or have an executed lease to secure financing to buy the second home.

As I studied earlier, the first thing you should do is marketing, then get a call and do a property analysis to understand if it's profitable for you, then meet with the seller and sign all the necessary papers, then if there is a debt in the bank we do a reinstatement quote, then do a title search to check if there are any hidden debts, if everything is fine we look for an investor or flipper and sign an assignment of contract with him and wait for closing to get our money.

The main issue is that to do the ADU you have to spend so much bringing other items up to code like electrical, plumbing, lighting (windows) and egress.

I’ve taken care of all my debt and am pre-approved for roughly $220,000.

Im self employed, roughly make $130k gross anually, 1099 NEC , no debt at all, 740 credit score. 

After closing, work on increasing your income, reducing debt, and preparing for a second mortgage.

Well, what would be happening is that your buyer would be buying your house subject to the existing note, since you can't legally sell the property without paying off that note or transferring the debt to the new buyer.

If you’re set on Florida, focus on areas just outside the main city that are still growing—you’ll find better deals there.