You are correct. The Ranger Bow teaches Capture, a 200 AP Hunter A-Ability. I don't believe sleep affects the catch percentage, but Concentrate (an Archer support ability that improves accuracy) might (I'm not sure, as I almost never have a hunter without Concentrate anyway, so I haven't tested it). I know that the lower the health of a monster, the higher the chances of capturing it are, although I don't believe I've ever seen Capture reach a percentage over 24. As to the use of the monsters once they are caught, well... Morphers use the "souls" you get from capturing a monster to duplicate the abilities of the monsters of that species (ie: capture a Goblin and a Red Cap, and a Goblin Soul will let a Morpher use both types of creature's A-Abilities). For info on feeding the monsters, I've provided lots of info available in the thread "Stupid flans!", and I don't feel like retyping it all, so I'd appreciate it if you would check that.