The legroom and seat width depend on which aircraft you get on. You can check the route by looking at the airline's website for the plane configuration and/or use seatguru to find the better/best seats for you.

As for the earning that too depends on what you book. The fare class will determine what you earn on the programs. LH & AC only earn on UA of the 3 programs you listed so you'd want to check UA's site for what the fares will earn under the Mileage Plus program for the fares you purchase on AC or LH.