The s7 edge from t-mobile should work with Koodo as their network operates on the same frequencies. Koodo, however will not take over a t-mobile contract. You'll need to pay full price for the phone if you want to get a different colour of s7 edge to use with Koodo.
It is not a thing in Canada (at least not for several years +) to buy out your contract cancellation fees like T Mobile et al do in the States.
According to T Mobile's site it is pentaband HSPA meaning not only will it work on Koodo, it will work on practically any HSPA network worldwide. It also supports the two LTE bands Koodo uses, especially primarily 1700.