My current Black 2 team; I'm going to have it half easy and half hard. Somewhat challenging with Iris.
My team in Black 2 consist of: Neko (female Liepard), Zaphod (male Watchog), Xandra (female Watchog), Dewott, Emolga, and Maria (female Mienshao).
I went with Pokemon I like instead of what a good team would be.
Shauntal (ghost types) should be easy. My Neko should take him down, she knows 3 Dark attacks. I will just need a few Hyper Potions, and for back up my two Watchogs also know Dark Attacks.
Marshal (fighting type) he is going to extremely hard, half my team is either Dark or Normal. Water types not too helpful, fighting type against fighting type isn't too good either - so I won't use my Mienshao. Just hope my Emolga can do the job, the only flying attack she knows is Acrobatics.
Grimsley (Dark types) - this should be easy for Maria, I believe.
Caitlin (Psychic types) - Again Maria, Neko, Xandra , or Zaphod should have it easy.
Champion Iris - it might be tough - her 3 dragons my Dewott or Zaphod should win if they can strike first, and hopefully the dragons miss their attacks. Both of them know Ice attacks. Dewott knows Blizzard, and Zaphod knows Ice Punch.
Maybe Dewott can take down but struggle with Archeops, its part rock, water should be good.
Hopefully Emolga's electrics attack can take down Lapras.
My only issue with Aggron, the steel type.
kind of long post - this is only for the normal game, not the challenging mode.... by the way, would this be considered a blog? (still don't know what they are)