You mostly got it right. If your shooters are for example behind cover and can’t see the mini(s) that the squad is aiming at, they won’t be able to shoot.
AFAIK the only thing you got wrong is the melee part. Your boyz will gladly use their shootaz to smash some heads in. They have one base attack. The boyz with choppaz just get more attacks.
Time to put some sanctions on tax havens then