As you are bouncing between states, can you try a different dealer?

Run the vehicle with the AC on & temp set as low as it can go while at the dealer so it makes the noise & ask if that horrid noise is "normal".

May be a bit harder to lie to your face while the vehicle is acting up at the same time right there infront of both of you.

Another option would be to call Ford Customer relations with the vehicle making the gridning noise & ask how that be normal or nothing is wrong as dealer XYZ is telling you?

Good luck!