This year is the first year I will qualify as a real estate professional and be able to take some aggressive deductions through things like cost segregation studies.

Based on the value of a property you can likely get away with a inexpensive desk top study such as condos and you will require a more comprehensive engineering study for larger properties like a 4plex.Desktop / modeling options are sometimes good for smaller residential like you mention. 

We have about 100 BRRRR examples and case studies we share with clients. 

So how is the primary residence and/or occupancy requirement “enforced” for example where in the process does it come up for the buyer to prove that they intend to use it for primary residence?  

Can they prove how long it takes to rent a vacant property?

Study the market.

Thanks for any help’ Yes we're licensed there and FHA guides in one state apply to all states unless a state has a specific law that supercedes the FHA lending guideline.FHA is always 3.5% down minimum (in some cases less because you're using a DPA or down payment assistance program or 2nd lender to put down over all a lower down payment than 3.5%, Aka for instance 3.5% DPA + 96.5% FHA = 100% financing but just dont kid yourself this is fully 100% leverage and to be used with caution and carefully).In the case of 2-4 unit FHA is still 3.5% down payment @Matthew Kwan @Carlos ValenciaThere are rules regarding FHA such as:- primary residence - you must occupy one of the 2-4 unit property as your primary over 50% of the year and the underwriter needs to believe you will remain and have the ability to live in there, any deviation from this and you'll get a whole laundry list of conditions asking you to prove why you should be believed to be living or will live there (if this arises dont be surprised, it just means the UW doesnt believe you).- SS rule - self sufficiency rule - gross rents of all potential units 2-4  X gross rents at 75% needs to meet 1:1 or 100% of the monthly PITIA payment or greater.

Study landlord basics, especially on what to include in your lease (going forward you will ALWAYS have a written lease).(2.5 Learn from mistakes and don't repeat them.)

Yes you can do a cost segregation study in 2025 still.

Study disqualified parties and prohibited transactions.