The problem you are running in to with TextEdit is very annoying, and Apple’s fault. The RTF format can actually handle footnotes just fine, in fact Scrivener handles RTF footnotes both on import and export. Pages on the other hand does not. So if you are exporting to RTF from AppleWorks, and then trying to import into Pages, you will lose your footnotes. You will lose them in TextEdit too. I think what the other posters suggested is a good idea. Find a word processor which will interface with AppleWorks (either directly or by correctly handling its export), many of them have demos (even Word), which should give you enough time to convert what you need before the demo expires.
Have you tried searching the forums here? I seem to recall one other person migrating away from AppleWorks. You might also try searching the web for solutions. The Pages solution might be good if it opens AppleWorks documents with all tables intact, and if it produces valid RTF footnotes on export. It might only produce them using Word doc format, but if that is the case you can at least use another word processor, like NeoOffice, to do a proper RTF conversion and then import into Scrivener from there.
Footnotes will probably be the easiest thing to solve. Tables on the other hand, that might be more difficult, and again this is Apple’s fault for having such lacklustre support of them.
Rest assured, there is probably a way to save your tables and footnotes, it just might require a little patience and trying a bunch of word processors and intermediate formats. The good news is once you do get a method, you’ll have your data in a format that is universal and this will never happen again (unless computers stop working, and then we’ll have bigger problems than footnotes).
As for the illustrations, it sounds like you composed illustrations in AppleWorks—probably vector based (drawing tools where you can select the shapes and move them around afterward). This is probably going to be something you will lose the ability to edit no matter what. Proprietary document formats are one thing, proprietary graphics formats are another entirely. GraphicConverter might be of some use, but since it is a bitmap (JPEG type) editor and not a vector editor, it will probably not be able to do much for you. I don’t have any experience with AppleWorks. I played with it once back in 2002 and promptly uninstalled it. Depending on how many illustrations you have, it might be easier to look for another graphics program (like Acorn, or DrawBerry which is free and might be more like what you are used to), and just recreate them from scratch, making sure to research and settle on something that can export to a solid universal graphic format like EPS.
I’ll reiterate the advice given by others. Your problem here isn’t really Scrivener. It actually does a better job of interfacing with RTF than most Apple document editors. But it cannot do anything with a bad input file! So getting that first step accomplished is important. The main problem is getting your data out from an obsolete format and going forward from there. Once you do, and your information is in Scrivener, you can be rest assured that this problem will be vanquished. Scrivener uses universally accepted formats, and as others have pointed out, they are stored in what amounts to a folder. In a worst case scenario ten or fifteen years from now, you’ll still have everything. That is absolute worse case. Scrivener, if it is still functioning in twenty years or whatever, has excellent export capabilities. You shouldn’t ever have to rely on mucking around in the project folder itself, but it is nice to know that ability is there if the worst happens.
As frustrating as the task is right now, it is worth it, because whatever difficulties you are having right now will be much worse, if not impossible, in the future.