I see that Roger has that little joey in his pouch, but the joey also has boxing gloves on. Is it possible to get the joey to throw a punch?
No he's just there so when Roger gets kicks in the stomach, the enemy feels guilty for killing a baby. I just made a dead baby joke. I feel bad now....screw you!
Check the command list.
Those are just the basics believe it or not(yes even King's long ass chain throws), if you do certain combos with them you get more.
Go on some sort of game cheat site, like GameFAQ.com, you'll find out there surely.