@Tom Dieringer you are correct that they are similar services.

Separate checking accounts not required, but you need to maintain separate books and records.The TREC requirement is correct, but odds of enforcement seem low.

I am currently moving through my first assignment of RPA escrow period and all of the seasoned people who shared their "assignment of agreement addendum" experiences and insight has given me the confidence to know I am moving in the right direction and taking the correct steps in order to close this transaction correctly. 

Since I'm doing this myself I did able to correct/complete them.

We purchased a property in early October and are placing it in service this week (mid November).We had intended to run a cost segregation study and try to accelerate depreciation which we can deduct against our W2 (assuming material participation).However, we have been reading through the IRS guidelines (eg publication 946 on Property Depreciation) and there seems to be the concept of "short year" which would mean that we can only deduct ~1.5/12 of a year's worth of depreciation in 2024.Is this correct or are there any different rules for STRs specifically?

Yes, that's correct.

That’s correct.

He is correct that you NEVER take the security for last month's rent for that exact reason.

Your definition is correct for "legal non-conforming".The "legal" part of "non-conforming" is dropped when it doesn't apply so most commonly people call these units "non-conforming", "finished", "in-law suite/unit", or "bonus unit".Non-conforming: Any property that doesn't meet current zoning requirements.Legal non-conforming: A non-conforming property that was lawfully established under previous zoning regulations and is allowed to continue its use.Based on his posts @Mario Morales is referring to a non-conforming unit.

Correct.