It sucks for the people that were hacked but I'm 99.9% positive that your bittrex deposit addresses are just that.... for deposits, once there their internal ledger accounts for those coins and those coins may be given away when they fulfill other withdrawals etc.... I might be wrong but I don't think so. So no use being paranoid about tracking the funds in your deposit address apart from deposits. Their internal ledger is what matters.
Yes, Bittrex, being an exchange, stores the funds in cold wallets.
The withdrawals are processed through their hotwallet.
Tracking your address won't work, as once you deposit your funds, they are transferred to the hot/cold wallets on the next sweep.