Do I want to back up my stuff? Or can I multi boot it with XP?
Ubuntu has a reliable option to automatically multi-boot itself during setup - you should back up just in case something screws up, even though it's unlikely. I'm not 100% sure if MoonOS has this, but since it is Ubuntu based it probably does.
If not, head to Google and look up tutorials for dual booting Linux. There's tons of them and it's not that hard if you know what you're doing.
What is a distro that doesn't require internet to do a lot of things, easy to use, and no Ubuntu variants.
Internet is almost obligatory for ANY operating system made in the past decade.
Ubuntu is as easy as it gets, but I would recommend
Fedora or something.
is it faster then ubuntu?
It is Ubuntu, just with a dock and different theme.