Main house (under)rented at $1200 a night average and the casita $300 a night. 

A CPA and lawyer should be part of your team but not necessarily from the same in house group for assurance purposes - @Paul Beets depending on your framework you should leverage the two separately of their industry knowledge, experience and network to grow your endeavors. 

If you invite the government into your business, you get the good and the bad.2) In my experience,(and I may get some hate mail for this) the average section 8 resident is harder on the property. 

It depends on what you are spending on the deal.Sounds like it is about 50% expense ratio at 54.55% which I think is along with industry standards.The net income looks like its $23,543 for the seller.What is his interest rate?

I've worked in the Television and Film industry for the past 11 years.

It needs to be an STR, which is defined as "average stay of 7 days or less"          3.

Real estate investing is forgiving; the average person can still make money even with some big mistakes. 

If the average tenant stays 2 years that is 5%.

In my estimation (local utility costs vary as well as temperature) it is about $400 per month on average. 

Between April 1971 and August 2024, 30-year fixed-rate mortgages averaged 7.74%."