Welcome, you have lots of variables in your process and ingredients, which is good we love challenges and it helps us think sideways so we better understand what WE are doing while helping you.
Are all the cheese you listed above, you've made from goat milk? Goat milk has it's own set of variables as I'm sure you know, it's naturally homogenized.
Also you don't need to use citric acid, you can use vinegar and a host of other things to do the same job. Your son has an allergy to citric acid? Does that mean he's allergic to a lot of food items? The only reason I ask is as a child I was allergic to milk, my older brother was allergic to corn and my younger half brother also allergic to corn..mind you we all grew out of it by the age of 12. Plus my mom is in the dental field and does a lot with universities, this meant she researched endlessly our allergies over the years. What she found out with my younger brother after years of research was that he wasn't actually allergic to corn but a super minute chemical used to process corn, so could it be something used to refine or produce citric acid? I only ask to help as it seems like citric acid would be pretty benign, but then again there are people who are allergic to sunlight.