Hey, I'm a fine, low porosity 2C-3A lookin' gal, too... so you can read what I use below, and also know that I'm currently curl-stalking KathyMack and MaggieT, who seem to have similar hair (except mine loves a few things that Kathy's hates).
I'm a science nerd: born, raised, degree, grad school, nerd city. My hair M.O. is the same psuedo-scientific approach I have to all issues:
Only change one thing at a time. (Clarification: you can use more than one product, but don't introduce two new ones at once, or even in the same week). If you change too much and aren't sure what is causing the problem, wipe the slate clean and start over.
I low-poo (a chem-free gentle shampoo) 1-2 times per week. It would be only once a week, but I do hot yoga and long bike rides, and it just gets funky. I feel like this keeps product build-up, even from great products, off my hair, which is important for fine/wavy gals. If I have a product-induced freakout, I also do a low-poo with some baking soda, to clean that slate.
I agree with JessieBanana about going through your stash again, or whatever is left. Just try one thing at a time, give it a few days, and if it doesn't work try to figure out why by reading up on the ingredients. Keep the products that don't work in a separate pile so you can compare the ingredients, and perhaps a pattern will emerge! Also, try using them in different ways and amounts. The first time I used KCCC, for example, I used as much as I would with a hair gel... and I looked BAD. Now I use a teensy tiny dab, like, I don't know a lentil (smaller than a pea), and it's dreamy for me.
Lastly, I'm not a big believer in whole product lines. In fact, if one product from a line works well for me, I can safely assume that no others will. It's frustrating, but I have fine finicky hair! So I just use what works, regardless of the product line, or even the intended use of the product. KCCC is almost like a leave-in, for me, even though that's totally not what it's marketed as.