That is a lot of salt for a 3 lb. bone-in chicken. Is there any way to achieve good results without so much salt. Need to be low salt (not no salt)

Actually it is not too much. This a similar to brining. General rule for a salt brine is 1TB salt per 1 cup water. In this recipe, it is 1TB with 2 cups buttermilk. The buttermilk marinate is rinsed off, in any case. If it needs to be lower salt, then marinate for 2 hours and not 2 days.