Quote from @David Sotomayor: Im getting into fix and flip real estate and working with a private lender who requires a higher credit score than mine to qualify.

Can they get pre-approved for a conventional loan and then switch to FHA once the 91-day requirement is met?

We're exploring creative ways to provide him with the cash needed for the down payment while avoiding triggering a taxable event.One strategy we're considering is purchasing his future primary residence ourselves, making the mortgage payments, and then, once we've built enough equity—comparable to the appraised value of his rental properties—transferring the title to him as a form of exchange.What are your thoughts on this approach?

Malibu allows it but requires a 15% "hotel tax" on the gross revenue.I would recommend looking out of state or underwrite the property as a long term rental in the event laws change.

Quick heads-up: Starting January 4, 2025, Pennsylvanias Act 52 requires anyone involved in wholesaling real estate to be a licensed agent.

Also do research on what's required to properly manage a LLC so the veil cannot be pierced. 

Your interest rate, on a fixed rate loan, should remain unchanged and your mortgage should not be called due.However you should still confirm that this is the case with your lender (and read your mortgage commitment) out of an abundance of caution and because some loans and programs do require a longer seasoning period.

@Emily Gowen so as you pointed out you would not have to do a 1031 exchange on your current home to avoid the capital gains tax and coupled with what Dave Foster pointed out I think, speaking from experience you would have a high likelihood of success. 

Most companies I’ve found require all tenants to be on a single lease, which doesn’t fit my plan.If anyone has recommendations for a PM company that allows individual room leases, I’d really appreciate it!

Call the registrar and ask. 1-800 321-2752 https://www.cslb.ca.gov/newsletter/2010-summer/page9.htmThe current text of ab968 requires FULL disclosure with copies of all contracts, permits and warranties within the two year window.