How to move a servo with a function
You wrote:

void runServoLight(
        int pos, int light1, int light2, Servo servo, int state)


Here you are giving the list of parameters used by the function. In C++,
parameters are by default passed by value. This means that, when the
function is called, the arguments passed in the call are copied into
the parameters listed here, which are local variables of the function.
Changes to those parameters will not propagate to the arguments provided
by the caller.
This can be an issue for the Servo object. This object keeps some
internal state, which has the memory of the current configuration of the
timers. Since you are working on a copy of the provided object, the
original object is not updated when you act on the copy. I do not know
whether this is making your program misbehave, but it would be safer to
pass the Servo object by reference:
void runServoLight(
        int pos, int light1, int light2, Servo &amp;servo, int state)

This way the object will not be copied: the function will instead work
on the original object provided by the caller.
The same may apply to the pos parameter. The very first thing the
function does with this parameter is to overwrite it. Then there is no
point in receiving that value from the caller. You can instead remove
the parameter and create a local variable with the same name:
void runServoLight(int light1, int light2, Servo &amp;servo, int state) {
    int pos;  // local variable
    ...
}

If you want the caller's version of this variable to be updated, you
could pass it by reference, just like the Servo object. It is,
however, more efficient to keep the variable local and have the function
return the final position. The call would then look like:
pos1 = runServoLight(lightON, lightOFF, servo1, 1);

One final point that is not visible in the snippets you showed: are you
doing edge detection on the buttons? Edge detection means that you act
on the changes of state of the buttons, not on the states themselves.
For example, you move from lightOFF  to lightON not when the button
state is HIGH but rather when it turns HIGH.