However, a parent and a minor child can open a joint account (checking, savings, brokerage).

He cannot 1031 his proceeds into the new joint venture deal with you as a partner in a partnership. 

We plan to create an LLC and joint checking account.

You can then build a business or joint-venture together.Investing with partners has it's own caveats as mentioned.

However you're talking to amateur here.Nope...The exemption, $250k single/$500k joint return is Per primary residence, not lifetime.20 years or so ago, the exemption only applied if you bought another primary afterward....that no longer applies. 

I am assuming that your friend is on title as a tenant in common or joint tenant and not simply a lender on this project. 

There fees are - ACH/Cash (via Chime deposit) payments are $1 per payment and -Card payments are 2.9% of the payment plus $0.30.

Spouse & I will retain ownership; joint ownership with Child isn't an option.

i dnt know what exists locally but i know in various countries they call it  joint ventures when people team together to buy property  legally with a solicitor to buy or invest together one might have money but not time the other has time but no money. or i have seen in usa  coops that i dnt quite understand b ut its seems a few people can buy a place with separate units together and not quite own a certai part but be part of the coop and there are ways with some properties to sell one unit . 

Hey Justin, The tenants should be "jointly and severally liable" for the duration of the lease.