will any exchange support callisto?
it seem no
yes or no, we don't know!!
Binance probably, as they already support the NEO airdrop, as well.
the litecoin cash fork took a while to get some exchanges on board, but yobit and mercatox ended up supporting it, I would be very surprised if no exchange is willing to support the ETC airdrop...hopefully a big name exchange will get on board soon, i dont care about the risk im parking my coins on the exchange that supports the fork, its a pain to redeem in a wallet then move the new coins to an exchange....imo only do that if you plan on holding callisto long term