Good luck with your team!

After you get the hang of MB a little bit, it may be best to take a step back and consider what your longer term goals are. While 4 hunters are probably extremely fun, please recognize that you will not be able to take all 4 to heroics or do many level 80 dungeons/raids. Also, if you're experiencing lag right now then I'd be a bit worried about 4-boxing in BC or Northrend. I currently 3 box and can never have more than one druid in Dalaran if I want to be able to move more than three steps without serious lag.

Most importantly, have fun!