Instead of debates and personal opinion, look for proof https://www.ladbs.org/docs/default-source/forms/plan-check-2017/single-family-dwelling-duplex-plan-review-list.pdf under G (Interior Env) which defines the minimum requirement of a habitable room (aka bedroom or bathroom).

Also, would this loan help build my personal credit, or would it only report to business credit bureaus under my LLC?

I personally again in my opinion only.. but these guys could be fake lenders.. for sure HML  do not have a requirement that they can only lend to a corp..

A one-person show isn’t gonna cut it.

You wouldn't need to keep an eye on other investments, just focus on the one and maximize your cashflow.If I can make a suggestion though...I might be wrong, but I don't think you started househacking to take the simple route. 

AND prices have come down a bit in the last few years.Get a good grip on your personal spending and CUT BACK on everything for a couple of years.

I had hoped to set this up with PNC since I bank with them but an in-person visit to the branch is required for set up and this is not possible since I now live in Washington state.

I agree with Andrew’s comments particularly because this is a home you personally lived in and know intimately.

While you are at it, put the next person on MTM to create some equity in the contract when you have problem in the future.

Quote from @Ashish Acharya: @Niklas Zhu If you tear down your STR in 2025 and convert it to personal use, depreciation recapture does not occur at the time of conversion.