Cities can require that the primary unit be owner-occupied at the time of permit application. 

Visit your court house, city hall, etc and see what you can find out about permitting and go from there. 

Do I need permits if I bring in a mobile home or similar semi mobile structure?

Vetting and screening vendors, ensuring your vendors are licensed and insured, maintain all necessary permits and licenses, maintaining appropriate insurance,  requiring vendors to list the deed holder as additional insured, execute contracts with indemnification clauses, being an active owner or have a PM who is actively checking on your properties to ensure there are no premises liability issues or property conditions that could lead to claims.

Investors often buy these properties with a plan to gradually upgrade units and increase rents, or even redevelop them down the line if zoning laws permit.

No General Contractor wants to do a remodel with the residents still living there....they will charge you more (they probably will not show it, but the prices will be higher because of the huge PITA factor and increased liability)I would wait until you have completely moved out and then just give them the house empty and ready to roll.....But you can get a Scope Of Work going and start getting bids...even plans and permits if you're going that far...

Explore assumption of the existing loan, if permitted

It adds a personal touch and helps guests feel more at home.Things to Be Aware OfLocal Regulations: Check local short-term rental regulations, including permits, taxes, and any zoning laws that may affect your ability to rent the property.Cleaning and Maintenance: Short-term rentals require frequent cleaning and upkeep.

You are permitted up to 90% combined-LTV between lender- and seller-financing. 

The local agent that was present at the beginning of the project had gone completely silent.Brandon - Back in 2021 I entered into a new build contract brokered by them and after 14 months into a 18-24 month anticipated timeline I had not yet been issued a building permit.