Nobody ever went broke over a duplex, I know this now,  but I have to admit I had some serious doubts about this when I started 16 years ago, I bought every course I could find, already on CD's, this was post cassette tapes lol, and I paid RichDad Education for a one year coaching program (turned out my coach was a girl in a call center without any actual experience). 

Four properties were existing STR's that had a permit 'transfer' and the other half were eligible properties that successfully launched with astounding success.

Transfer from personal name to LLC/Due On Sale ClauseIf one is transferring property title from personal name, a Grant/Warranty Deed would be drafted/recorded to transfer title.

Transfer of the Property or a Beneficial Interest in Borrower.

LLCs are a legal tool, not a tax one.Transfer from personal name to LLC/Due On Sale ClauseIf one is transferring property title from personal name, a Grant/Warranty Deed would be drafted/recorded to transfer title.

These are business purpose loans so there isn't any sort of red tape when purchasing multiple properties at once or one after another.

If you are setting aside funds for capex, taxes, insurance, or other expenses that don't occur monthly, transfer those funds to Savings each month and hold them there until it's time to spend them.

So, things change a bit.If it is his personal home, there are more restrictions.For an investment property, if you take over his financing, read through the deed of trust (mortgage) and see how they handle transfer of ownership.

Is there a way to transfer the loan agreement to my name or try some owner financing/selling strategy?

I believe your loan could get called if you transfer ownership to an LLC without consent of the lender, especially a brand new LLC that does not have two years of tax returns.