All 9 characters are crocheted with an E hook and whatever yarn I could find to match the colors (mostly acrylic, worsted weight) and stuffed with polyester fiberfill.
The characters were crocheted from the bottom up, starting with the feet and crocheting up to the head. Next, I attached any jacket/coat as a separate piece. The exceptions to this were Inara and River, who were initially crocheted as a flesh-colored stick (from foot to head) with the dresses crocheted separately around them. The arms were crocheted separately (usually crocheted as a flat rectangle and sewn into an oval, though occasionally crocheted hand-up in the round if there were multiple sleeves showing) and attached symmetrically to the body using the yarn ends. Ears were also crocheted as separate pieces and sewn on. The eyes consist of two double-knotted pieces of black yarn, with the ends weaved through much of the body to prevent them from pulling out. The hair styling was a lot of fun, and generally involved giving each character a pretty fully head of long hair, trimming it down to size, styling it appropriately, and gluing it in place. Jayne's hat was knit with size 1 double-pointed knitting needles in the round. It's not attached to his head, so any character can try it on!