House flipping partnership models

I bought my house as a foreclosure. Our realtor worked with us two years to find the right deal. This real estate agent also has a side business flipping houses bought at auction with her uncle providing financing. We used her main contractor for our renovation and had a great experience with him. He’s done other smaller home projects for us the last few years. I also learned a lot on this renovation as I was getting my own plans and pulling my own permits.

Heard the uncle who was providing financing for the flips is retiring now. I’m considering going into the financing part or in a possible three way partnership with the realtor and contractor where we all put up money. I’m told the housing market here is still relatively hot and the last flip sold for 45k over asking.

Anyone here have experience flipping houses with multiple partners? What kind of contracts or profit splits are people doing? Essentially, what is the best model for this and what mistakes have you learned from? I’m partly interested in this because my wife could be involved with these projects and file taxes under Real Estate Professional Status which would probably save us $35,000 in taxes with just that. Thanks in advance for the help.