I'm doing my roof and plan on using 30# felt and 25 year shingles. Standard is 15# but 30# only costs twice as much (you get just half as much on a roll). I live where the wind likes to blow and can blow shingles off. What is overkill to some is just added protection to me. Do what ever you want. You live over there where you get those ocean winds and noreasters where you might want the added protection. The 30# doesn't tear as easy also when the hurricanes hit. Whatever water that blows up under the shingles or gets there from ice dams only has the felt to keep it off the sheeting.
Most roofers around here consider 40 year shingles overkill also and mainly because we get enough hail that even 25 year will outlast the hail storms before it is replaced. I agree and don't think (for me anyway) that the price difference is worth it. If you are spending the money for 40 year shingles, then don't scrimp on the felt. Also make the roofers use the wind installation method recommended for your shingles. Usually 6 nails instead of 4 and cementing all edges down as well as extra cement (quarter size dabs) under each shingle. Good luck on whatever you do.
I also use the best 20 year paint I can find even though painters around here claim you still have to repaint every 10 years because of moisture problems.
I personally haven't used the ridge vent system but some are beginning to around here. I have read posts on this board where snow will still blow through the vent material and into the attic. Then it melts on the ceiling drywall. Of course all vents (except maybe soffit vents) are subject to wind driven rain and snow. Good luck. Been to your beach a few times and have enjoyed it.