Ultimately, you want a CPA and Quickbooks...that is the magic combination.If you are looking at financial modeling or more sophisticated solutions, we use a VA Firm called UpWork...some pretty bright folks out there. 

EYA does build a great product.

You can google and find products ranked by reliability.

You want an advisor that can help you strategize and who is responsive when you want to know the consequences of the financial decisions you are making throughout the year.You should also look for a Fee-only advisor who is not going to sell you a product and/or try get a commission.

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. 

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.