Seller financing wizards, I need some aid!

[Erik Sanders]

Hey BP Community!

I found an incredible deal (a bit out of my price range) but trying to ask HOW CAN instead of can't.  

With some finesse, I got the seller to agree on some creative financing. I so have some questions on how a partial seller carried contract is structured through Title and with a loan legally. Here is the situation:
-Asking price was $1.55M, negotiated him down to $1.4M total
-Financing is through a DSCR loan at 15% down (for an Airbnb)
*my problem is that I only have enough funding for a purchase price of around $1.1M, so I got the seller to agree to carry a contract for the remaining $300k at 10% APY interest only payments until we refinance.

Final terms:Total cost $1.4M (loan for $1.1M and $300k carried by seller)

Questions: Do I need to mention to the bank that the seller is carrying a partial contract? Or would they only need to know that the seller agrees to a purchase price of $1.1M? I do plan to have a PSA with the seller privately with the carried contract terms for the remaining $300k.

Secondly, how would this work through title recording? Does the seller need to get placed as a second lean on the property and be listed on the deed?

Any professional insight would be great here! Home is in Phoenix (85020) for reference!

Thank you all!