ok so far wario just drives the bike, the bike runs people over, and getting run over hurts like a ***** so it will do decent damage.
yes the characters can pick up the bike it shows mario doing just that, and if they can pick the bike up they will most definetly be able to throw it, how far depends on the bikes weight and the characters strength.
you are knocked off the bike by having wario get hit, although hitting the bike hard enough could cause wario to momentarily loose control
if you are knocked off the bike while on the ground the bike will most likely keep running for a few seconds before it loses control due to lack of driver and steers itself sideways, bringing it to a stop. fer god sakes its a motorcycle not a magic carpet. now i dont mean to be mean, but we have to remember that this is a regular motorcycle so it will most likely behave like one.
oh and i do see yer point now