Let's deal with the servos first.
attach() them in setup()
write() a value to them in setup() or loop() and they will stay in that position
Don't want them to move ? So don't write a different value to them
As to the stepper
Move it to a position and it will stay there
Don't want it to move ? So don't move it to a new position
For both the servos and stepper it would be convenient to put the movement code for them in a function. That way you can call it when required.
What actions/inputs should start the stepper and/or servo moves ?
Call the movement functions when the input signal is received and not each time through loop()
What order should they occur in ?