I've had these SAME problems with hair products. Our AA daughter is 18 months old also. I tried the :just for Me" products but didn't really like them. Our daughters hair is also very course & curly. I wash it every 2-3 weeks but condition it every day. I don't rinse it out. Every couple of days when she gets a bath I give it a good scrub but with just water. When I comb her hair everyday, i spray it with water first. Then I put in NEXXUS HUMECTRESS. Not the generic version though. I comb it through & leave it in. I let it soak in for about 15 minutes or so . Then I apply a conditioning hairdress. Then I style it. Maybe give that a try. It seems to calm the frizzys. I also use the same products on our Biracial daughter's hair. I just have to wash hers more often. I asked our daughter's birth Mom what to use on her hair.
Asking around and experimenting is the only way you'll find what works for your daughters hair. Also maybe get the book "it's All Good Hair" by Michele N-K Collison. It tells all about AA hair, products, styling, etc. I found it very helpful.
Deb