The software I use for cleaning up audio was developed by some people who were doing cylinder-to-digital for various libraries (including, I think, Library of Congress). Works very nicely, and not horribly expensive (though you *can* pay a lot for some other products if you want to go serious pro, or zero if you want open source with some kinks). I've hardly had to use more than a small sampling of the tools available to make some very beat-up old records sound almost new - sometimes better than new. Only way to do better, I think, would be to have access to the original masters (tape or whatever), and even then a light touch with some of the cleanup tools (to, for instance, remove a bit of crackle or tape hiss) can help.

You JPEGs on floppies won't be readable in 2114, even if you can find a working drive. Bit rot on magnetic media. Some "gold" CD & DVD makers claim their disks will last that long or more - hard to prove, and finding a working CD drive might be just as hard as finding a floppy drive is now (I have both common PC sizes!). Move them to new disks (current technology) every 5-10 years to keep the files alive. JPEG itself has a well-documented standard that should be available in various archives, paper or otherwise, so using the file should not be a problem if can get access to it.