If someone wanted to stay out of sight and completely anonymous using tails, and electrum, would it be possible to do this by downloading tails and all necessary files from a clean computer and burning the iso onto a dvd? Would the DVD somehow copy some important information from the computer in which it was burnt from?
Also, if I wanted to make multiple usb offline wallets, could I just install electrum onto the usb sticks or do I need tails on each of them?
The computer that burns the DVD should not put any additional data onto the DVD (hidden serial number, hidden data, etc.) I've actually tested this on a Linux box. You can burn the DVD and then copy the DVD back to the hard drive. The checksums of the original Tails ISO will not match the copy of the DVD. The reason for this is that the DVD will only burn in 32K blocks of data while the Tails ISO is not a multiple of 32K. The way to fix the problem is to subtract the size of the Tails ISO from the size of the copy of the DVD and then add that many zeros to the end of the Tails ISO. If you recalculate the checksums of both files, they will now match.
As for the offline wallets, you could boot Tails from one USB and then put the different Electrum wallet USBs in a second USB port. This seems like it would be unnecessarily complex, though. Probably a better method would be to store Electrum on the encrypted persistent partition along with a file of seeds for the different wallets. You should be able to switch between the wallets by saving each one to a different file name (1-9?) and then just do a "File->Open" for each different one. (Note: I played around with this just a little bit to see if it looked like it would work. Test this extensively before putting any major amount of money into this system.)
Make sure that you create an encrypted backup of at least your seed list. (You should backup your entire persistence partition). USB flash drives are notoriously unreliable.