This will be a lengthy post; I apologize in advance. 

You can certainly prorate this, but you will need some pretty lengthy disclosures.  

The only resources I've found are Fannie/Freddie guides that are very lengthy yet unclear in certain regards.

Ryan, there is no statutory form requirement for sale of real property in CA.The rather lengthy explanation from the young man taking law classes fails to correctly answer your question.

However, most buyers want to lock in the future purchase price upon inception of the lease option.During the term of the lease option, the buyer agrees to lease the property from the seller for a predetermined rental amount.The term of the lease option agreement is negotiable, but the common length is generally from one year to three years.The option money generally does not apply toward the down payment.A portion of the monthly rental payment typically applies toward the purchase price.Option money is rarely refundable.Nobody else can buy the property during the lease option period.The buyer generally cannot assign the lease option without seller approval.If the buyer does not exercise the lease option and purchase the property at the end of the lease option, the option expires.The buyer is not obligated to buy the property.Basics of lease purchaseBuyer pays the seller option money for the right to later purchase the property.

Most prefer to avoid this cumbersome process as can be lengthy and expose a simple sale between parties to overbidding by 3rd parties who get wind of the court sale. 

I have heard about sellers signing over the title, yet still technically owning it, but it makes the eviction more difficult and lengthy.

They know multiple market niches and strategy's and, at least in a good market, they can make better returns than any other type of RE investor based on their lengthy experience in Real Estate. 

The lengthy back and forth process with the SEC and the legal cost of constructing one of these offerings demand that the money is invested on a discretionary basis by a fund manager of some sort.  

I have a lengthy Legal Opinion, from my seasoned Legal Team regarding this matter.