Kristen Daniel , like you said there are two key questions to answer. How are you going to bring value to someone who already does this and second, what is a worthwhile rate of return for you on your capital. You are in a tough spot. If you need the partner to being in capital and also do the work, then you are essentially just a glorified lender and so the return you can expect to get cant be that much. The reason I suggested you fund the whole project and let the partner do the work was because now your actual cash on cash return is way higher and also the partner is now able to do another project that he/she might have otherwise not been able to do because of being capped out. This is very common in my world - spec home building.
Builders have credit lines with banks but once we reach a certain amount of projects, we cannot borrow anymore until we get one of those under contract. At this time, if we were to get a deal, I would pitch it to my investors. They would finance the project and provide the down payment and my company would manage the entire project and we split the profits. In most cases, the investor makes between 70% - 80% cash on cash return. This is what a lot of spec builders do. Maybe you can reach out to some local spec builders and see if that opportunity exists. Whatever you decide to do, just check references, their track record and make sure the partner is trustworthy.