The bulk of the rules you encounter on your taxes will be CA specific, which are usually more complex than other states. 

Specifically, criminal background checks, credit scores, rental history, etc.

Consulting an attorney who can review your specific  mortgage note would be well worth the fees on this one, good luck!

I should note, VRBO default now copies the Airbnb model so you’ll need to call vacation rent payments (vrbo provider) and specifically request advanced payments.  

@Gary CalverThere is a prep agent state specific course that is 50$.

You can also ask more specific questions and get better advice from the BP community by doing this.

You need to nail it down for your specific area.

HOA debts remaining are state specific.

But remember that only capital gains can be excluded under the 121, not deferred depreciation recapture, so you'd need to speak to a CPA about your specific situation to make sure you know what's what. 

I am about to use Shelter Home Mortgage (specifically Bradon Dainas) for financing on a triplex.