The vertical lip will be on the ocean side. Stop the water from the side. I think that alone will keep a lot of water away. One for each screen. $10 solution. Sort of.
You also wondered about closing the helm. I assume you looked at Privilege. But also look at the Excess range. They put a little silly roof over your head but the idea could be extrapolated. But, for sure, no matter what, the minimum is a windscreen and a roof.

I started with an open power boat and the most freezing trips I have done is in the late afternoon going home. If I ever sailed that would never happen again.

I don't know if you are considering a stern anchoring solution but I find that imperative. Helped me many times. ( mine was muscle powered). I hear Privilege is using something called a "flat rope winch" but that's all I know. Again, in aluminium that could be designed in a jiffy. A bow thruster is a must. That two engine maneuvering in a crosswind is overrated. Marinas are so full nowadays, sometimes one has to work with inches. If at all possible even a stern thruster.

And make sure that platform idea at the wheel has a sturdy rail. I would not like to sidestep off it into the cockpit. And all windows glass of course. No plastic of whatever type the gurus are selling.

Good luck with the project. I will be watching. But I have a feeling that this boat is going to be world class. From safety to beaching to everything nautical.