From my experience and what has been echoed here in these responses is that if the fundamentals of the location, the traffic counts, the visibility, etc. 

For mortgage swap eligibility-related reasons (we don't have the net worth to qualify for the swap as individuals, but do have enough to qualify as guarantors for an LLC as the borrower; the swap is about 40bp better than what the bank can offer us directly), I'm exploring taking title to the new property as an LLC.  

Say a R6 lot, which is already eligible for 2 builds, has a good standing structure (house).

Also, would I still be eligible for a FHA loan if my first property was done through seller financing?

not if you occupy this property because the sole purpose of a DSCR loan is a rental product so the mere mention of DSCR implies non owner occupied plus DSCR lenders dont like borrowers who dont atleast own their primary residence first (some rare DSCR lenders will not require you to own something but most will want you to own your primary first to be eligible).The above is clear cut and unedited version of the guidelines so most of the other stuff posted is a truth albeit a partial truth, convenient, but with out context.If you have questions feel free to reach out and we'll address any other questions you might have. 

Would I just label all eligible expenses as such?

One of the best is the Neighborhood Assistance Corporation of America (NACA).NACA was formed in 1988 and provides an affordable option for potential first-time buyers:✅ No down payment✅ No closing costs or fees✅ No mortgage insurance✅ No consideration of credit score✅ Below market fixed interest rateThere are several requirements to be eligible for the program, starting with attending a local or virtual workshop.NACA.com…you can get your first set of keys in 2023!

You have to be self-employed and no business you own can have any full time employees to be eligible to open a Solo 401k. 

If you plan to hold on to this property long-term, think of the fundamentals:1) Transportation - being near a transit hub is incredibly valuable.

For reference, here is the Fannie Mae Eligibility matrix and it might help you when you expand on your question.