Through-hulls closed in winter?

One of my (many) off-season projects will be replacing the old gate valves in my hull with properly bedded Forespar Marelon seacocks. I have read that you want to keep all seacocks closed in the winter except the cockpit drains, but I'm not 100% sure about the underlying theories.

What I would like to do is start removing the gate valves and through hulls now, prepping the surfaces as I go. If I do that, there's a very good chance that cold weather will set in during the project and I won't be able to finish bedding the new fixtures until spring. Of course, I can grind the hull in any weather. It's just the epoxy / bedding compound curing that concerns me.

The boat is on a cradle right now in New York, so real cold weather is approaching. Would having a few through hulls missing over winter be such a problem that I ought to wait until warmer weather or is it no big deal to start now and finish later?

Thanks,
Chris