yeah, there are a lot of options with this system... Too many to think about.
I will look into needle valves, do hardware stores carry them with 1/2" NPT?
The tankless has a 6" stub of a vent, you can see 1/2" of it protruding on the top. I am probably going to just ad a 90° turn to keep it away from the cooler.
I am interested in going electric, but my garage is opposite of my electrical panel, and I have no 240Vac over there. In addition, the service panel is in the basement, the garage is on a slab obviously, and routing the electrical service there would require me to cut out the back of a closet and the basement ceiling... not fun.
I kept the build that long since I might shift the cooler stand over a bit to give more room for the tankless heater. As it is now, the tankless heater will overhang by about 2 inches. Additionally, I wanted room for a 100qt kettle in case I ever needed it, and they are roughly 20-21" in diameter.
Thanks for the thoughts and feedback, keep them coming.