The Gotham Blades would probably have the same color scheme as the other Gotham teams which is Black and yellow. But to make it a bit different, I went with a slate grey for the main color on the home jersey which is unique to the NHL. No team wears grey for their main color.
The logo was something I thought up one night. Naming any team "the Blades" leaves you with very little logo design ideas. Usually teams called the Blades have a hockey skate for a logo. But I thought a sword would be cool. Something simple. The "G" behind the logo (for Gotham) is in the shape of a shield. So you have a sword and shield for the crest. Im not a logo designer, and Im sure someone could make this basic concept a lot cooler.
For the Metropolis Mammoths, I went with the first idea that came to my mind, a simple mammoth head holding a hockey stick. There are other sports teams with similar logo's so its nothing to unique but it would work.
As for the color scheme, I have two. One is brown and orange with teal and the other is blue and orange with teal. The brown and orange color scheme would be something very unique to the NHL. This team would probably be very old and maybe they kept their original color scheme for a long time. The blue and orange isnt unique, as the Oilers and Islanders have a blue and orange theme. But the teal would add a little bit of a unique look. Orange is my favorite color so I like both. I'm not sure which one to go with.