My hair has been dyed red for many years and my hair was damaged, thin and super porous two years ago but is SO much healthier now thanks to going Curly Girl. I've never found shampoo to be any good for colour retention, I got by far the best results from conditioner only washing in cool water and a leave in rather than a wash out conditioner.
If you do your roots with a permanent dye but your lengths with a high pigment semi permanent you won't cause any more damage. If you have killed the curl by damaging the protein structure you may not be able to get it back to 3a/ 3b, some of the damage may have to be cut off (sorry).
Coconut oil is wonderful for damaged hair, but it may not absorb if you are applying it over the top of products containing silicones, ditto proteins may not absorb effectively if you have any silicones on your hair. I suspect the Organix and Fructis are packed with silicones, these impart faux shine and slip but do not actually improve the health of hair.
It's worth reading the ingredients lists, the actives the product claims to contain are often so far down the ingredients list as to be pointless. When I did this I discovered I was just piling silicones onto my hair with little in the way of ingredients that actually penetrate or 'nourish' hair!
2a-2c, medium texture, porous/ colour treated. Three years CG, growing out mechanical and chemical damage = breakage and very high porosity. Past armpit length heading for waist.
CO-wash: Inecto coconut
Treatments: Komaza Matani, coconut oil, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume, Inecto argan
Styler: Umberto Giannini jelly, Boots Essentials gel
Experimenting with: going back to basics