1. Can't be partnership. Partnership has to dissolve if someone wants to leave.
2. If it's LLC with annual distribution there has to be difference between managing members and non-managing menbers.For non-managing members there is the issue whether their investment is fully at risk, because the tax treatment is different. If there is no distribution it will be easier, but then you have to pay and give 1099 to managing members (thinking long term, there may be many of them at different locations) and do all the tax s--t.
3. When you say guaranteed return, it means a note of guaranteed return rate, but not a secured note, because before you buy the property there is nothing to secure on.