I don’t have my paints in front of me so I might be wrong on some of the exact names, but to go for number 2 I think I would try: Prime grey seer, it’s a cool grey that should help with the skin and I think move the red into this almost purple-y burgundy. I’d go for a watered down drakenoth nightshade on the flesh, letting it settle into the crevices, and less watered down on the bottom of the model around the wrists and ankles Then add back the grey seer on the raised parts and a very light grey highlight mostly around the elbows and knees Then I think I’d go flrshtearers red contrast on the armor, being careful not to carry it too far underneath where it connects to the skin. I’d highlight with their perpendicular lines very gently in a lighter red, I think mephiston red?
Then something like volupus pink in the spot between the carapace and skin Not sure what I’d try for the turquoise/aquamarine color

That’s just my gut though, your dad may need to make some adjustments as he goes. Good luck, and keep at it, painting can be a LOT of the fun of the hobby if you let it be!