1. I can transfer this token from NXT AE to BTER and back?
The actual asset itself, UNITY, yes. There is an intermediate asset TOKEN that will be issued until the end of the process.
And this token can be tradet then at every exchange which accept this TOKEN?
2. At launch there would be a wallet which includes every coin inserted in the SuperNET?
As I understand it, yes. It will be based on the NXT wallet, with shared functionality of all the coins' features. But others will be able to say more about this.
Are you sure? A NXT based wallet which i can deposit/withdraw every coin in the included in the supernet? Then would be superfluous the NXT multigateway!?