It sounds to me like you wouldn't want to setup anything where these people have any say what so ever since you say they are just "nosiy" and are looking at the wrong things.
It would seem to me like you would just want to set up your LLC and they are "angel investors" if you will. This way they have no say over what is being done with the money. They will of course want a percentage back which you can structure with various options such as:
1. They get a percentage of each deal that is completed with their funds based on the total funds needed to complete the deal.
2. Next is a straight up return, much like a CD at a bank. You offer to pay them back X% per month for their funds. This of course will be a much lower number then what they would get if they were to hold out for payments. This would likely be around .5-1% higher then the average rate for a CD in your local area.
... those are two ways to accomplish what you are trying to do with as little hassle with regulations as possible and with as little interference from uneducated investors.