[dnanian]

A safety clone shares many applications and files with the main drive -- those are the aliases you're seeing. Totally expected, but please note that it's not a backup for exactly that reason!

It's up to you how you want to try out Tiger. Since it's best to have a full backup, I'd probably try it on the Safety Clone first. If you're happy with it, it's easy enough to install it on your main partition, and you still have a backup.

If you install on your backup, you don't have a backup any more...