Make sure you're performing credit checks, background checks, verifying income (calling employers and even checking bank statement if you need to), and calling former landlords to inquire about/confirm their habits as a tenant (cleanliness, respect for neighbors, paying rent on time, etc.).If you don't think you're capable of this, definitely find a good property manager!

If you want your LLC to be respected for liability purposes, it should have an operating agreement, bank account (so an EIN) (this will also require disclosures to the bank on your identity), and for you to full respect it as a separate entity from yourself. 

The additional person also increases the chances they have funds in a bank account that can be seized, as well as other assets that can be seized (verify bank vacuuming is allowed in NY). 

Assuming I had the experience, I would only buy a place with structural issues if I had 1) an experienced and trusted structural engineer telling me a clear, and verifiable explanation of the cause(s) of the problem and a viable and affordable solution, 2) trusted and experienced tradespeople who would be implementing the solution (carpenter, mason, etc.) confirming with me that they could fix the issue (with 90% or higher confidence that the issue could be resolved within budget), and 3) confirmation from city inspectors that the issue (and an inability to fix the issue) would not result in condemnation/revocation of occupancy permits. ...and even then, I'd only proceed if I had the cash reserves to ride out a major series of unexpected problems (e.g.; time overruns, budget overruns, unexpected revocation of occupancy permits from the city, etc.) 

Verify both fit the LPs goals.6.  

I would recommend speaking with a lender in your area, or better yet, reach out to the servicer of the FHA loan you are intending to assume and verify your ability. 

In addition, the owner of the home must not own more than three single-family homes.3) They are unable to provide sufficient documentation, such as the emotional support animal letter, that verifies the ESA is necessary for their health and well-being.4) The tenant provides fraudulent documentation attesting to their need for an emotional support animal (usually a fake emotional support animal letter).5) The landlord can demonstrate that making accommodations for an ESA would impose undue financial burden or logistical burden. 6) The animal is destructive to the property or displays threatening behaviors that could put other tenants or yourself at risk.7) The size or nature of the animal makes it impossible to house safely or humanely.

What I know about this house is that there should be no mortgage (messaged realtor to verify), last sold for $60k in 2004.Rent in my area; $1,200 is usually pushing it but doable.https://www.realtor.com/realestateandhomes-detail/200-Walnut...At the end of the day, I love the idea of seller financing but I have many more questions when it comes to different types of properties that might be mortgaged and how does one pay the monthly payments on top of paying the equity to the seller at the same time.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

I won't call him a GP because I never could verify that he was a GP in any syndication, ever.