What achievements will be lost or unavailable after the World of Warcraft: Cataclysm expansion is released?

In preparation for Cataclysm I've been trying to complete achievements I feel will be lost or converted to "feats of strength"; achievements like Eastern Kingdoms and Kalimdor lore master, Classic Dungeon Master and Raider, etc. My first question is, does anyone know of a resource that lists which achievements will be lost or unavailable after the expansion is released?

My second question is: if I really want to get exalted with say, Hydraxian Waterlords before going on to Cataclysm, but need more time than the December 7th release date, can I choose not to install the game and keep the world the same? Or will they be releasing a patch that removes those achievements and makes changes to Vanilla WoW regardless?

And finally, will any Burning Crusade or Lich King achievements be lost? I feel like those are probably safe, but that’s just a guess. I'd like to know for sure.

If TL;DR, here are the questions:

1. Which Vanilla achievements will be lost with Cataclysm’s release? Or will they all be lost?
2. If I don’t install Cataclysm, will I have more time to get achievements done?
3. Will any Burning Crusade or Lich King achievements become unavailable?

Also, if you know of a great achievements resource in general, please list it. I'd like to see which are easiest/most realistic to get done in this month time frame. Thanks.

1) Most classic achievements aren't going anywhere with Cataclysm. Of those you cited, none are going anywhere, though the requirements for some are changing (If you already have them, you don't need to worry about it, but if you don't, you'll need to meet the new requirements. In some cases, these are actually easier than the old ones - Zul'Gurub is being removed from Classic Raider - in others, it's essentially resetting all your hard work on, for instance, Loremaster, if you don't finish. Some other changes:

• Did Somebody Order a Knuckle Sandwich and Master of Arms were changed to Feats of Strength in Patch 4.0, with the removal of Weapon skill. If you missed out on these, it's too late already, sorry!
• The Green Hills of Stranglethorn, and with it, the collected Nesingwary achievements, are - somewhat surprisingly - not going anywhere.
• With the removal of Zul'Gurub, The Deadliest Catch - will become a FoS, and no longer obtainable. Similarly, if you have any interest in a rare Raptor or Tiger mount, with it's attendant FoS, you have about a month left to farm one up.
• Zul'Gurub is also where you go to farm rep with the Zandalar Tribe, whose reputation is being removed with the Cataclysm. You can also buy this rep off of the AH in the form of a whole lot of token turn-ins.
• Since you asked - the Hydraxian Waterlords, (and Molten Core), aren't going anywhere. You're welcome to keep farming that rep well into the expansion.
• Finally, while Insane in the Membrane is not being explicitly removed, several of it's requirements will become impossible after the Cataclysm. Notably, there will no longer be any way to gain Bloodsail Buccaneers Rep (which also means if you want that Bloodsail Admiral title, you're running out of time for that too...), and the Librams needed for Shen'dralar rep no longer drop anywhere, and the NPC's to turn some of them into have disappeared. Ravenholdt will still be doable, but significantly more grindy, as the Syndicate mobs which you used to be able to kill to get to Honored have been removed - it's Junkboxes all the way to Exalted.

2) No. When the Shattering happens, it happens for everybody, regardless of their sub status. The world changes will be reflected in the vanilla game, and not buying the expansion is not going to buy you time to work on old achievements. The clock is ticking!

3) There are no TBC achievements changing as far as I know, but several Wrath raiding achievements are going to get the FoS treatment, since attempting them at level 85 trivializes them. These include the various ToGC tribute runs, The Immortal/The Undying, Champion/Conqueror of Ulduar and He Feeds on Your Tears

An easy way to check on future availability of any achievement in which you're interested is to look it up on WoWHead, and then click on the "Cata" link in the top left corner, which will show you how it is being changed in the Expansion (if at all). If it's been recategorized as an FoS, or had it's criteria changed, you should see the difference.

I can't answer your other two questions, but vanilla WoW zones will be updated regardless of whether you own/install Cataclysm or not. Get cracking! :D