Will TNT be traded on the bittrex exchange?
Sure, someday it should happen, they add tokens pretty fast, especially top ones, as TNT is.
Btw, MeW is not the best place to store your tokens. I mean security, you trust all the data to a 3rd party server, though it is the most convenient way.
What's the issue of leaving the coin were you bought it. I.E. LIQUI or Bitrex?