I know it's a different team of writers and such, but in the beginning of Supergirl they introduce the head of the DEO as Hank Henshaw who features pretty prominently in the comics as the real name of the Cyborg Superman and such. That turned out to be a total red herring as
he was really Martian Manhunter
.
Of course,
the real Hank Henshaw could have survived the fall somehow and is being put back together to still come back as that villain, but I think it was totally meant to throw off the audience.

"Philosopher Stone"
Yes, LOL- when I read that, I was like, umm, they cast Tom solely based on this factoid alone, didn't they? or he's a red herring.
Too early to tell; I don't want the answer to be something that predictable but I also don't want him to be some random character who just happens to jokingly irritate Barry. They already have their core team in place.
Website
https://lilgripes.com/

1: The second Alchemy was a CSI in Central City's sister city, Keystone.
2: He uses an artifact called the "Philosopher Stone" Tom is best known for Harry Potter, which began with the Philosopher Stone (Outside of America anyway.)
Darth Maul: "He Lives"

I have my suspicions but I would be disappointed if it were the case given how predictable it is.