I have a few questions about it... Does it just switch names and gives the pet all the stats, food, color...etc associated with the other pet or does it just switch the color Ex. George has read a ton of books if I name swap with weirdo will he have all the books George has read? (And species, color, etc) Also if you rename a pet does it keep its legacy status? Or will it have a new created date?

Yes, the name swap only switches names. If you swap George's name with Weirdo, weirdo will end up with all the books George has read. It's basically just a cheaper alternative for renaming.

And renaming doesn't change the legacy status or creation date.

Thankyou c: