[Routine Help] Is it safe to use BHA, Retinols, Niacinamide, and Vitamin C in the same routine?

Beauty Tips For Body Care
The three actives I'm currently using are salicylic acid(Paula's choice 2% liquid exfoliant), adapalene gel(LRP effaclar 0.1% gel), and niacinamide(TO niacinamide 10% + zinc). I use the niacinamide daily at night, the adapalene every other day, and the SA once a week when I'm not using the adapalene. I'm thinking of adding a vitamin c serum to help clear acne scars and PIH. Is it okay to use all four in the same routine?
Girls Blog 2015
Submitted by Stan_without_ley