Quote from @Alek Fort: Hello,If you are both in agreement on terms and %, then I would think almost any title company would be able to assist you with both the contract and closing. 

The benefit to the seller is that they get 0% down deals with lower than average interest rates for commercial deals (Seller carrying 25-50% note at negotiated 0% interest) and have theoretically infinite returns with 0% down.

Three questions: 1) do California Realtors have a seller financing addendum that they can use? 

I learned about Groundfloor at a RE seminar.

The builder is also surprised that the sq ft came out that high.

@Andrew CosmeYou should close just as if it was a normal sale and get a title company to create the loan docs, get title insurance and sell you the property.I strongly recommend you go through a title company and do not do a closing that was based on docs found online etc.

@John Anderson definitelyjust make sure the HOA allows investors purchase and rent from day 1.based on your budget, I know of another HOA in DFW that is allowing new builds for investors.

You’re going to pay this entity more money than anyone else in your life.If you're successful, that could mean that you will pay them millions over the course of your business career.So who is “this entity?”

What is a bit fuzzy for me is once I find that motivated seller, how/where do I find a wholesaler's contract?

Just make sure you’ve lived there for at least 2 of the last 5 years, which it sounds like you have, so you should be in the clear.As for timing, since both deals are happening around the same time, things should move smoothly.