Cut dairy completely. Also try to 'sweat' it out a few times a week by doing cardio/running, etc.

I find that a lot of sunscreen brands have broken me out in the past - make sure yours doesn't have any irritating ingredients. Coppertone Pure and Simple is cheap and hasn't made me break out. I like Vanicream daily facial moisturizer over Cerave.

Your current regimen is already pretty gentle. Don't really have any recommendations because I don't have active acne but I do have redness and discoloration. Neogenesis serum and barrier cream has been helping me fade my marks so far.

I agree with @avensisit looks like you're using too many products, which can actually lead to irritation and more acne. Also, don't make the mistake of using too many exfoliating products. This will only make your skin more oily and susceptible to breakouts; Differin by itself is plenty powerful. Babying your skin, as opposed to nuking it with products, goes a long way.