that wont work dude. simple as that.
first off, you cant have variable range on a weapon.
secondly, you'll either have no muzzle flash on the rifle, or muzzle flash on the melee.
you be better off making a rifle with projectile attack, and a rifle with melee. then the player can switch between the two, depending on how subtle they need to be.
multiple/secondary attacks are not possible within the current limitations of FPSC.
although.. (this is the edit), I don't want to make you negative, you might find a solution, so.... give it a go.
"Guns for show, knives for a pro."