I have done joint ventures before but have all been structures as equal partnerships with capital investment and share of profits.

Odds are good that you jointly file taxes and comingle finances other ways.

I prefer a ACH from their bank, check, money order, or cash...in that order.There was a recent blog post with a real world experience on what happened with a 3rd party processor that allowed credit cards to be used. 

Tracy Good MorningSome times it is worth paying to get rid of a head ache.

Any advice on finding a joint venture partner for your first flip and how to structure the deal with them?

Looks like you are really describing a joint venture for your next RE investment adventure - and I would suggest that you choose an entity structure that is jointly owned by your personal business entities (i.e., your LLCs, or whatever your formal personal business entities are - please take your personal business entities beyond sole proprietorships!).  

Be cautious about putting sealant on brick joints.

For my crack they will do the same; however, where bricks are cracked and they do not need replacing - they will grind the brick down and put in a mortar joint.  

The limitation was created as part of the 2017 Republican tax law to offset other tax cuts to firms in that legislation.Suspending the limitation will cost taxpayers about $90 billion in 2020 alone, part of a set of tax changes that will add close to $170 billion to the national deficit over the next 10 years, according to the Joint Committee on Taxation (JCT), the nonpartisan congressional body.The provision has fueled criticism by congressional Democrats and some tax experts who have called it a giveaway to the wealthy and real estate investors, who frequently face large losses on their investments.

Finally, join a local Rei group and find someone more experienced to do a joint venture.