It seems like every city, county, and state has its own rules, permits, and tax requirements for short-term rentals, and I’m finding it overwhelming to navigate all the different layers of compliance.For example, some places require business licenses, transient occupancy tax permits, or even special zoning approvals.

I've already contacted the county planner and was told I'm not able to convert this garage to an ADU because of setback requirements.

LTR tenants are required to have the home professionally cleaned. 

you can get financing witha  LLC but the lender will require a personal guarantee on the loan.

What type of transaction fees should I be looking to pay and is there a down payment required?

I just learned this has now become a voluntary requirement for the time being as there is a court order to stop this reporting.

Windows would be my next check-point (less than R1) and then wall insulation: I would not be surprised if they have no insulation inside, but you can do blow-in, which only requires a small hole.A home looses heat in two ways: heat conduction (which you can slow down with insulation) and drafts, which in old houses is usually the biggest culprit.

If I own a STR and it is operated by Vacasa, then I sell the property to someone else who still wants Vacasa to manage the property, this wouldn't require Vacasa to take down the listing and make a new account/listing. 

US treasury rates increased ~80 basis points since the beginning of October as polling results started coming in and the increase continued post-election in expectation of high government deficits and sustained inflation (due to tariffs and otherwise). 

Most lenders typically require a 30% downpayment.