Its kind of pointless to try and figure out why things are the way they are in Macross lol I used to think about this kind of stuff all the time, and eventually I got to the point where it didn't matter any more. I don't think the VF-0A two seater was meant for training, if that was the case the 0D, even though its a supposed electronic warefare aircraft, would also be a training aircraft mainly because we've seen Shin training in it. I honestly think the 0A two seater was meant for jobs that most two seater fighters were meant for, aside from electronic warfare stuff the 0D does. Make sense?