Chizuru is a fairly active sort of girl--she is an athlete, after all, and she takes it at least semi-seriously. So she jogs a fair bit, goes down to the tennis court to work on her serve, etc. She does like using the Internet, but isn't quite the hobbyist Chisame is; her main focus is finding cheesecake, heh. Also, being Chizuru, she spends a fair bit of off time hanging off of Chisame--either reading over her shoulder when Chisame's on the computer, or trying to weedle her off the computer for a little physical affection. 8D
Koumei...sleeps. A lot. This is seriously like 3/4ths of her day sometimes; she'll just slip in and out of naps. If she's awake and doesn't have anything else compelling to do, though, she'll read whatever's available to read (as long as it's not insultingly stupid) or meditate or plot strategy, though she doesn't do much of the latter because, well, she doesn't have anyone around to actually assist strategically. She also fishes.
Sayo sort of wanders around and tends to strike up little random conversations with people who can see her. She likes attaching herself to people whom she's particularly fond of and following them around for as long as they'll let her.
Mana does mostly training-type stuff--target practice, other forms of combat practice, cleaning her weapons, things like that.
Himeko runs around doing random stuff or looking for random stuff to do until she runs out of energy and falls asleep. XD Like Tomo, she's often on the lookout for people she likes to hang out with/bug, but unlike Tomo she tends to forget about such specific goals (i.e. one moment she might decide it'd be really cool to go see what Kubota and Tokitoh are up to, but the next minute something shiny will catch her eye and whoa what was I doing again? 8D).