We lived in a little apartment above the garage and rented out the main portion of the house. 

What are some things I should include in the lease?"

I live in NYC and started investing in Buffalo a few years back, mainly for the reasons that you mentioned. 

Bad contractors are one of the main reasons why first time investors never do a second deal.

For your payout, I don't know the full story but Airbnb doesn't cover extra fees including cleaning fees.

Lenders stopped allowing rent by the room due to modifications done to the property resulting in functional obsolescence and significant cost to cure in the event there was a default and they needed to foreclose on the home and resell it, given that the main buyer pool for single-family homes are primary occupants. 

We are in Tampa so a similar market.We provide a starter set which is clearly communicated to guests (thought some people do not like it and clearly do not read which you cannot help) generally consisting of:- 2 Laundry Pods- 2 Dishwasher pods- 2 Rolls of Toilet Paper per bathroom- 2 Paper Towel Rolls- 2 Trashbags- All soaps are refillable including dish soap, hand soap, and body washes/shampoos.They are expected to get their own should they run out of anything. 

These included cash buys for flips, seller financing, and subject-to deals.

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.

Construction is mainly CMU, Concrete, and Steel (at least for my projects), and there is a bottle neck of those resources as only few supply the area.