int analogPin = A0; // 5 Potenimeters. each 1 controls 1 motor
int analogPin2 = A1;
int analogPin3 = A2;
int analogPin4 = A3;
int analogPin5 = A4;
int analogPin6 = A5;
Nothing, 2, 3, 4, 5, 6, huh?
Have you heard of arrays? You code would be much shorter if you used arrays.
Serial3.begin(1000000); // Servo Communication Speed
That's 8 times the highest supported speed.
Is it necessary to send 6 values because one changed?