I just found out the answer recently, I might as well pass it on. You can change your wifi character simply by heading into the union room and listen to what the lady sayes. She should say something along the lines of lets change your title to "roughneck" or something like that, anyway then exit then head into the trainer card and click the arrow, it should change the title and the character as well.
Wait for a wifi event
Yes
Yes, they can.
You lose all of your pokemans
you have to trade over wifi or have a friend with Pokemon white and trade. you can only catch it in Pokemon white
Do wifi battles and make sure to do triple battle
By using WiFi or IR or in-game trades, the list goes on and on
Have fun do some battle subway or do wifi battles
probably
You can not get him while playing a game. I believe there will be a wifi event in which he will be given.
you have to look around the victory road, or you can trade over wifi.
It's presently unlocked via a wifi event. Liberty ticket gives you access.