I'm not really sure why exactly they decided to "make him old", I'm sure it's important enough for them to want to do that. I'll have to see when the game comes out! It'll be amusing to defeat soldiers as some old guy though, either way.

That taunt is nearly impossible, I just had Krile stand there with every character while I kept jumping in and out of boxes, trying to do it xD Eventually I managed to do it for everyone. I still haven't done the Star Fox ones myself.