Well they could have pulled the same thing with A,B and GH, seeing as the only reference we get is a statement by duke that they were injured.
could be interesting to see how well the animation matches up to what he is saying. We never hear about them until the end, which is done only by voice over, just like when they say Duke is doing fine.

no.... somewhere, within the last year, there was an interview stating that Alpine, Bazooka and GH were not meant to make it. I am positive I read the same thing. I think it was rather new information that nobody had really knew before. I read the same thing, it's out there, and the info was from someone who worked directly on the series.

Unless this was massively early stuff that got cut out long before the film went to animation, I'm doubting this.
Again, Duke's entire survival was via changing the script in post-production to add the "coma" and "Duke'll be fine" lines. For them to do that, but animate the surviving characters appearing throughout the film, seems unbelievably unlikely.