I don't know of one product that'll get the job done that you want. I have to use 2 products: one as a leave in conditioner and a second product to define curls/reduce frizz/add shine. There is this creamy leave-in called Abba Moisturizing. It's gentle enough to use on a kid. Then for the defrizzing, there are a couple of products that I use. Beyond the Zone Noodlehead curling cream is available at Sally Beauty Suppy - comes in a tube. It enhances curl a lot. If you'd like looser curls, there's a gel called Kinky Curly that you've got to get from beauty stores that does the same without as much tightness of curl. Neither creates curl out of thin air, but both take generically curly hair w/some frizz and helps enhance it to defined curl with more uniformity. Neither makes your hair crunchy either. One last technique is to top it all off with Wave Nouveau Moisturizing Mist. It will not leave behind any greasiness, but keeps hair almost as soft as it is when it's wet, even after hair has dried.
I second what the other person said about not washing too frequently (common mistake - black hair doesn't oil up much on its own, needs added oil it's so naturally dry and non-greasy).
Most of your solutions are going to be a little pricey, and most will contain some type of silicone-related thing - it's a great de-frizzer. But without the leave-in, the silicones dry out your hair long term. I'm not a big fan of Miss Jessie's Curly Pudding because it's expensive AND has a strong mint smell that's obnoxious, although I heard that made a special low-scent formula for babies. There are lots of products, but you're going to have to go to a good beauty store, not just Sally's, if you want advice. The higher end beauty supply stores usually have a whole section dedicated to curly hair products (Miss Jessie's, Mixed Chicks, Kinky Curly, etc) for people of all races. Since all of us (black and white) are a bit mixed, it's hard to find the exact products to control your particular mix of curl. Also, check out naturallycurly.com. It's got a great forum.