I've unlocked the rat, but "Rat Monarch overhauled" - he seems to be the same. The tooltip sayes lower health and mana and doesn't mention damage, but his damage is still the same as it was (even though it's not mentioned anywehre).
EDIT: Found the Chemist. You might want to change his intro text about the "al" bit, it's inadvetedly quite offensive to any arab, as it makes it sound like using their original name for something they kinda discovered and systemized, "Al" being "The" in arabic, makes it less scientific. And they're quite proud of coming up with quite a bit of it. If it wasn't bastardized Al Chemist would be "The Chemist", except stupid period appropriate europeans thought it was one word and sucked at it early on, which is why now Alchemist is synonimous with fiddling with chemisty in ways which don't have much scientific merit. Alchemy simply means "the science/knowledge of chemicals", wasn't the people who named it who went around trying to do silly things with lead. Not kidding.
The Rat intro was great and charming, props for that one, but do consider what I said about the chemist intro. This isn't just insulting to rural jihad-happy koran-thumping arabs (who probably won't ever play DD), this is inadvertedly insulting/racist to perfectly fine run-of-the-mill/educated arabs who just might.