I'd forget about WD40 and use PB Blaster.
You have pretty good list already. Much depends on how long you plan to be there and whether you're traveling back and forth. Using the Import Permit in Mexico will allow you to bring stuff in duty free, or have a friend do it for you. Much also depends on how long ago you changed, for instance, your raw water pump. The seals do go and a new shaft is always handy, but it is easier to replace the whole pump - only if you aren't capable of changing the seals. Much is up to you. I replaced my raw water whole pump in 1998 when we bought Aquavite, and now see some weeping which means I have to choose to either have the seals replaced (for almost the same price as a new pump), buy another new pump, or do the seals myself. Them's the choices.
By now, however, having the boat for a while, you should have a pretty good idea of what you need. In addition to light bulbs for nav lights, for instance, when was the last time you changed the lenses or put new fixtures in? Only you know that. I've been working on replacements over the years and now have new bow, stern and steaming lights. Replace the anchor light with LEDs.
While an alternator's on the list, don't forget the regulator, they go out a lot more quickly than alternators.
An alternator belt tensioner is a great tool. See pictures:
http://c34.org/bbs/index.php?topic=3667.0And exhaust elbows last five years, depends on when you last did yours.
And get a battery monitor. As I noted earlier (see:
http://c34.org/bbs/index.php?topic=4454.0), my estimate of amps used was right on, but how much goes back in is even more important and I found the acceptance rate of the batteries reduced the final few amps for a full battery to hours of charging, so if you're NOT going to be tied to shorepower at least once every few weeks, go solar (big array) or you'll be sorry.
Electrical wire and connectors and good electrical tools needed to replace that pesky starter fuse? The list goes on...
Also, I think I'd suggested George Benson's harbor hopping the coast book and blog log (
http://c34.org/bbs/index.php?topic=4533.0). Makes using the engine even more important and avoids brain beating offshore work.