At 32, I had just moved out of my first 4/3 house (that I own jointly with my brother) and started renting it out as my first rental.

Start at the tub and work towards the door....that way you aren't trying to work with a thin piece near the tubBefore I snap in the piece, I would probably put a big bead of silicone down on the joint between the tub and floor and then put the plank down so the silicone gets a good seal to the plank..... then later put another bead on "top" of the plank to tub joint

When I divorced I discovered my x had taken credit cards through our joint bank account.

The interest need not be equal, and, in the event of the death of one (or more) of the owners (co-tenants), no right of survivorship in the other owners exist and the interest of deceased co-tenants passes to his or her heirs.JOINT TENANCY WITH FULL RIGHTS OF SURVIVORSHIP- An undivided interest in real estate property, taken by two or more joint tenants.

Would the neighbors be open to some kind of joint venture agreement?

Open to joint ventures and all that good stuff. 

. - doesn’t require a level floor so no bouncy boards or squeaky flooring joints. - so easy to clean as there are no seams for gunk or smells to work into.

Should I try to find a new bank that can do a joint account?

I have properties we could joint venture on.

Use a high end click lvt and glue butt joints together with g-2 loctite.