I finally beat this game and my unanswered questions have finally been put to rest.
I now know what became of Allen and Garnett; and even Leggett - what his dark secret was. After having played the first two games before, when I was confronted with the truth, it actually hurt. There was a sting of hatred towards Leggett and also even a sense of sorrow.
But nothing prepared me for Red. First we thought he was dead. And I was relieved that he wasn't. But the end cutscene was just cruel. Yet such is the way of war. Red gets to go home. Some part says its a good thing he will get to see his wife and daughter again. Then the other part says - but why did it have to be this way?
If anyone wants to play this game, they really have to play the first two games. And play them in quick succession. Reason: you bond with the characters. You truly begin to see them as your squad - especially by the second game.