I mean... I can't possibly recommend that particular order. I would definitely plug the new one in first, get it the way you want, then wipe the old one.
+1 to the above... You can have AppleTV's mirror the Home Screen of the original, which should set them up exactly the same way. I do this in our household where we have three AppleTV's, but no matter which, they all look the same (same apps installed, all icons in same spots, etc).