Joint Venture - tips?

[Christina Torres]

My husband and I are looking to buy a portfolio of properties. Given the sellers are my parents and they just want a monthly payment (they don't want us to get financing and pay them the full amount because then they will be taxed heavily) we are looking at 2 options- leaning towards the second.  

1) Seller financing - the downside to this is that at some point we will refinance because BRRRR..... and they will get the remaining money owed in one lump sum

2) Joint Venture- in this scenario my parents put up the properties and we put up the rehab costs and ongoing management. BUT how do we determine how much equity our contribution and work gets us? if the prop is currently worth 200k and we're going to spend 100k, I think it seems fair that we would have 33% equity and from there 50/50 on any increase in the value. Should we ask for additional equity for the management of the property and how could we determine the value of that? Also what professional would be best able to advise on the ins and outs of setting something like this up (and if you know of anyone in the Chicago area please send me their info!).

Anything else in regards to either of these we should be thinking of as pros or cons? TIA!