Little Em Asked: Pokemon Black: Team Help?

I'm Playing Pokemon Black and right now I'm training my team up to Lv.35 before I get to Driftveil because I heard Clay's pretty tough. Please give your opinions on my team and any comments on move sets. Also your opinion on what I should switch my Herdier out for, and what to put in my sixth slot. Oh and I have a friend who has White that's helping me out by teaching useful moves to my Pokemon and trading some extras to me. If that helps :). Thanks in advance.
Team: (All currently Lv.28, training to Lv.35)
Dewott
Nature-Quiet
Moves-
Revenge
Surf
Icebeam
Focus Energy

Musharna
Nature-Gentle
Moves-
Psychic
Zen Headbutt
Shadow Ball
Hypnosis

Gigalith
Nature-Timid
Moves-
Tackle
Bulldoze
Power Gem
Headbutt

Zebstrika (Will not be used against Clay)
Nature-Naive
Moves-
Pursuit
Flame Charge
Charge
Spark

Herdier Lv.27 (Swapping out)
Nature-Mild
Moves-
Take Down
Tackle
Work Up
Crunch

Here are the Pokemon that I'm considering to replace Herdier or be in my sixth slot:
Mienfoo
Gurdurr
Scraggy
Litwick
Pawniard
Deino