Sellers then get a notarized copy of lease and a separate option.

I would get seller's right, tax write off for the mortgage, and a notarized promissory note outlining our agreement that he is responsible for 50% of the mortgage and will handle tenets and manage repairs. 

Even taking affidavit's to this effect or having the LMO take a notarized statement from the borrower that they are happy with all terms and price.  

. === here's the Calif Form, observe, it's a Proof of Service, not a Notarization === Proof Of Service I, the undersigned declare under penalty of perjury, that I served this Notice to Pay Rent or Quit, of which this is a true copy, on the above-mentioned Tenant in Possession in the manner(s) indicated below; [ ] On ____________________, 19____, I handed the Notice to the tenant. [ ] I handed the Notice to a person of suitable age and discretion at the tenant’s residence/business on ____________________, 19____. [ ] I posted the Notice in a conspicuous place at the tenant’s residence on __________________________, 19____, [ ] I sent by certified mail a true copy of the Notice to the tenant at this place of residence on ____________________, 19____, Executed ____________________, at _______________ By ____________________________________________

A notarized copy is then recorded with the county.

If the title company provides a notarized letter confirming that the recording is in queue with the City, that may resolve the registration issue.

A notarized letter of authorization is required if a person other than the owner applies for registration.

We were looking into a very small mobile home park (5 leased hook-ups, 4 leased park-owned units) and contract required tenant estoppels (where tenants sign a notarized documents stating that the property is in working order, the leases are accurate, there are no side agreements, no money due from seller, etc etc).  

Then I would do a purchase & sale agreement with the seller, get an authorization to discuss the loan with the lender, along with a notarized Quit Claim Deed, (I learned to use a Warranty Deed later), get the reinstatement amount, send in the reinstatement and bring the loan current, give the seller their equity so they could move, record the Deed and take over the financing Subject To.

My stepfather signed a (notarized) will and quitclaim deed to me in the hospital just weeks before he passed away.