This is my daughter's hair. She has a ton of fine, cottony, 4a hair..dries quickly, tangles very very easily. Her hair is down her back, however I never have it down..its in twists 99% of the time, b/c I don't feel like dealing with the detangling sessions any more than I have to. For a down look, I'll just unravel the twists.
Hair like your daughter's and mine needs something that will "fill in the cracks" in the hair shaft and smooth the cuticle down a bit. Products that work on my hair are like water on hers..nothing.
One thing I like is the Shea Butter moisture lotion. Its very lightweight in texture, however it seems to keep her hair moisturized better than any other sort of leave-in, also helps get me get a comb through itSometimes I mix it with water and put in a spray bottle before twisting her hair.
She would probably benefit from sealing as well, have you tried that? Maybe put the lotion on first and then seal with coconut, castor..vaseline..?
her hair sounds like mine. and my hair likes that Shea Butter Moisturizing lotion. this is the thing. her hair will respond better to products that are of a thin consistency or liquidity. once you use those, you can use a light oil like coconut, jojoba oil, grapeseed, etc... i like avocado oil for thicker. castor oil might be too thick.
my daughter has low porosity as well. i use liquid first, a moisturizing lotion, then a styling cream to smooth and seal. i wash/cowash her hair every couple of days and i dc once a week.
for our liquids we use Taliah Waajid Bodifier Mist, Wave Nouveau Moisturizing Mist, and Hawaiian Silky 14n1
for moisturizing lotions we use Oyin Hair Dew, Taliah Waajid moisturizer for kids, Kids Organic Shea Butter Detangling Lotion, or BB moisturizing lotion with castor oil.
for cream i use Taliah Waajid styling cream for kids.
i always work with dampen hair with my dd, then i apply the liquid moisturizing, lotion, then the cream when i am ready for styling.
i also mist her hair throughout the day with a watered down Taliah Waajid mist (heavily watered down)
my daughter is 3b/3c but it can be very dry. i am a very coily 4a. my hair tangles easily relaxed or natural.
i use the Wave Nouveau Moisturizing Mist on my hair and use jojoba oil to seal. very light and not greasy.
but to sum everything up, you need products that absorb into the hair, not just sit and coat the hair. that is why i suggest products that are thin or liquidity.