Correct, beams are (possibly confusingly;) not lasers. We are actually fixing some of that confusing overlap with some different part breakdowns in future builds.
When in doubt, if you equip something and it doesn't bump your stats in the Hangar, it's not going to in the game. The exception is the rank'd stuff. We are going to be trying out more and more stuff tied to those to help with balance and creating more interesting choices of which Servo to take when.
Next build will have the big specials unlocked by rank as you play. The big missile barrage will be a later game thing, but it will have an early smaller shot.
On the "do the buffs apply at rank one?" question... In your build, I think not. I don't have that build setup ATM, but IIRC, that has head buffs applying at rank 2. You can tell if you swap heads in the Hangar. If it changes the damage value there, it applies the buff at rank 1.
