R1: Correct! Now he's got only a light weapon.
R2: I think that his value is 5 points.
R3: Yes. A marine must discard his heavy weapon and use a light one.
R4: Maybe, the player that gains the Secondary mission token is the one who has replaced its rocket launcher with a bolter.
AND, also, he must win the Primary mission or must be the one with the most points at the end of the game.
But it's only my hypotesis in the case that two or more marines have replaced the rocket launcher.