Is there a way to transport my choices from first game on Android to second game on Xbox One?
According to this post on Steam forums it's only possible between Steam/iOS and it isn't official but a fan made tool. The user, Aleonymous, is also registered in the Banner Saga forums and seems to have certain reputation or even know the developers as seen here therefore I believe that's correct as of today.
Also, as far as I know, there isn't such thing as a Stoic/Banner Saga account.