An update:
I called WDW -- a very frustrating experience because the CM was not a native speaker of English. Let me say, honestly, that I do not have in me what it must take to leave one's home country, learn a new language, and take a job that consists of speaking that new language on the phone. I do not have the strength nor the will to do such a huge thing, so I do respect those who take that leap. At the same time, it is frustrating when it's so hard to make yourself understood and get the help you need.
Bottom line, though, is that as I suspected, simply having our confirm # at check in is enough and they can re-print the various package vouchers for us. The CM on the phone first tried to tell me that because I booked online, I wouldn't receive anything by mail! (I nicely explained that this is our fourth trip in four years, that the past 3 trips were booked online, and that we had ALWAYS received luggage tags and check-in documents and vouchers in the mail ahead of time). Let me also clarify here that we are NOT using ME (took forever to explain this to the CM, too). Obviously with ME you really DO need those special tags. I'm just looking for the regular WDW luggage tags and my pouch of information.
CM said they'd reprint the information and re-send it (although since she thought I shouldn't have received anything anyway, I'm not sure how she made the leap to "re-doing" something, but no matter). Maybe I'll get it, maybe I won't. If we get our little luggage tags I will be delighted, if we don't then we will still have a magical, merry trip. But you know the bottom line -- it's plain old customer service, and those little touches that you look forward to because they are fun. Sigh. But hey, they know we're coming so I can't complain!