With respect to zincs on non-conductive surfaces: they're useless unless bonded to, connected to, wired to, the metals they're supposed to protect.
With respect to bonding: there's still chatter about whether it's best to bond all the underwater metal or not. My guess is that if the boat lives at a dock it's necessary due to the risk of stray currents, and not so important if the boat is a long distance from others and does not have its own problems with stray currents.
With respect to paint failure at the waterline: bottom paint is not made for not being immersed; topside paint is not made to be immersed. That boottop area is neither fish nor fowl and is hard to keep painted, let alone successfully repaint, on any boat.
Lovely boat! Have her surveyed by someone who knows wood. Wood boats are maintainable, repairable structures but you have to stay aware of their needs and plan ahead. (There was a lovely wood Egg Harbor in our marina whose only failure was shabby frame heels; sad to see her going in a dumpster for, what?, 1% of the wood?)