As to the cost, I would also expect Jerryll to cost more than Carrot for a more custom product and, hopefully, better results. 

Many others are quoting 12months from contract to closing.our process is  2 months to get permits from first day of submission.. and 5 months to build.. production builders 4 months. 

You will DEFINITELY find lenders/brokers selling a nearly identical product in the 7s and 8s but don't settle for that. 

Have you heard of this distinction between appraisal prices for owner-occupied vs investment property?

Just becareful as once you "scale" this idea, I THINK you can run afoul of the Security and Exchange Commission (SEC) since it becomes a syndication or some sort of regulated investment product. 

So revised plan, the product you want/need does exist.

I know Meridian bank offers a product like that but often the problem is that it needs to be non-owner occupied for hard money.

@Nidal DaraisehUS Bank has a construction to perm loan product.

Try to find a product that has an add value ability from the exterior items, the interior concept including washer and dryer location.

Or what financial products should I use?