plug your steppers into the ramps (that 4pin thingy) the reverse way (1234 --> 4321), it will move in reverse and it should make the endstops "see" it in the correct direction.
is your extruder stepper the same size? the drive frequency of steppers may hit audible range, it is quite normal, there are ways to make the frequency higher (inaudible to us, but your dogs may go crazy)
is your extruder stepper the same size? the drive frequency of steppers may hit audible range, it is quite normal, there are ways to make the frequency higher (inaudible to us, but your dogs may go crazy)