Crunch vs. Shadow Claw = Crunch is better. Nothing's immune to Crunch, at least, though there aren't too many normal types in Ubers.
The only thing Reshiram needs coverage against is Heatran. In which case, Earth Power is the best move.
Zekrom @ Choice Band/ Scarf
Ability: Teravolt
EVs: 252 Atk, 252 Speed, 4 HP
Nature: Jolly/ Adamant
- Fusion Bolt
- Outrage
- Dragon Claw
- Crunch/ Volt Switch
OR
Zekrom @ Leftovers
Ability: Teravolt
EVs: 252 Atk, 252 Speed, 4 HP
Nature: Jolly
- Bolt Strike
- Outrage/ Dragon Claw
- Hone Claws
- Substitute
The only thing Zekrom's STAB moves cannot cover is Ferrothorn & Excadrill, and the latter is not a wall so it won't be a Zekrom switch in. Everything else will be neutral or super effective. If you really want to cover Ferrothorn, your only option is Focus Blast.
I would suggest Dragon Claw for the Hone Claws Set since Outrage confuses you afterwards, and Zekrom is liable to do substantial damage to itself without the attack boosts.
Reshiram @ Choice Specs
Ability: Turboblaze
Nature: Timid
- Dragon Pulse
- Blue Flare/ Fusion Flare
- Earth Power
- Draco Meteor/ Focus Blast
OR
Reshiram @ Life Orb
Ability: Turboblaze
EVs: 252 Speed, 252 Sp. Atk, 4 Def
Nature: Hasty
- Fusion Flare
- Dragon Pulse
- Flame Charge
- Roost
So while most people prefer Draco Meteor over Dragon Pulse, Reshiram would cutting itself short by using a move that decreases Sp. Atk by 2 stages. The Flame Charge set is meant to see it stay in for as long as possible, keeping its speed boosts from Flame Charge, and a move that forces it to switch out is making the set mute.
