I'm not an investor yet but can refer you to someone who does flips here.

Hope your "far away from other rental" units are close to some commercial.City or County housing authority keeps participating landlords on file and are usually happy to refer folks.

If you need references for either of them in San Diego, let me know.

Just for reference, our interest rate is 7.2% with an all-in mortgage (PITI) of $2,040.

Any references for that are appreciated! 

Seemingly if I made this an ADU instead of a duplex I wouldn't have to rate these walls, once again complicating the intent of the code.Just above the code section I reference one of the exceptions to fire-rated walls includes exterior walls of individual dwelling units on the same lot, which may eliminate my need to rate those exterior support walls.

Thank you so much Denise, so the new law you are referring to is HB. 270, correct?

It's in Grand Rapids, MI for reference.

When you say "institutions" are you referring to the lender?

As I mentioned this is my first property and I got to this point without too many questions since my realtor was really helpful, but my property manager wasn't as helpful and she mentioned that I should discuss this with my insurance agent, That I don't really have one reference to trust, so also if anyone has a good insurance agent from Utah it can be helpful.