I haven't seen any new ally on test, but I'd assume that if we do get an ally we will only know about it when it launches on the live servers. (Though Teekl would be sweet)
Vampires, man-bat, werewolf ... an ally where it would not be so obvious that this is some kind of iconic character ...
A.) whatever you're taking, it's working; unless you're supposed to be taking it, then it stopped working B.) 100% would use. I support this post.
I dunno about purely Halloween theme allies, I can see it, just can't think of many (maybe Sofia Gigante, but that's a deeeeep cut). but Teekl has me thinking - and I know people have mentioned this a LOT - but Iconic Animal Pets, Allies, and Henchmen. Krypto, Streaky, Isis, Teekl, Ace - even a henchman team that's Krypto, Ace, and Dynomutt (Dynomutt's a stretch I know but ...)