Low-po hair has a tightly closed cuticle...the heat helps to open the cuticle. Putting the shower cap on is sort of a mini steam treatment - it warms the hair to open the cuticle. Also, leaving the conditioner on for longer gives it more time to absorb.

You have more discipline than me to just try one or two things at once. It's the best approach, though!!

Yes, the suave coconut has protein - silk amino acids.

Glad you are finding some success. It can be frustrating sometimes but it's worth it!!
remember, with all advice or suggestions for your hair, YMMV!!
My hair:
2b wavy, medium texture, low porosity, med-high density. Protein finicky.
My routine:
Cleansing: DCNP, every 4-5 days (occasionally use CJ cleansers).
RO: CJSC, occasionally use JCDC
Gel: KCCC, CJCIAB for 2nd day hair (sometimes third)

Heat is my friend: warm water rinses, steam caps, and diffuse dry. I love CLU cloths and my Denman.