Have not had gall stones, so not within my experience.
However, low fat dairy especially is high in lactose (carbs) one may be good for one condition but not for another.
I'm my experience, I have had to tailor my own personal dietary requirements, due to the factors in my life, and I had to get that balance right for me. A food diary and testing before and after meals gives you the knowledge of how your body responds to food, drinks, fats, oils, carb content,
Your individual dietary regime will be to your tastes, geography, availability and how it is cooked.
The recommendations for low carb is general. The actual circumstances of your diabetes dietary requirements is up to you.
Best wishes.