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.

It’s better to start small and gain experience than to get stuck overanalyzing.Keep the questions coming!

Having before & after pictures is a string tool when dealing with HMLs and real estate agents to gain business. 

Hire a company/person that is solely a QI like @Dave Foster they do it every day and will keep you legal and on track. 

Leverage your existing equity to invest in smaller properties, such as a mixed-use or retail space, to gain experience and cash flow.

- Also, what is their networth, so they are legally collectible for the guarantees?

Signing the lease demonstrates they agree to the terms and then you can hold them accountable.If you don't do this, then the person named on the lease and paying the rent could disappear and you would have no legal authority to charge the remaining three for unpaid rent.

LLC's main benefit is from a legal perspective.

Ultimately it was sorted because I clarified they legally had a joint responsibility to pay the total rent and there wasn't even an option for "half" the renters to pay late.

The buyer pays taxes on the crypto gain and the seller pays taxes on the property value gain.