Sounds like quite a good team. There's no type overlap, meaning there won't be as many shared weaknesses. I'll recommend sets for all team members.
Cinderace @ Charcoal
Ability: Blaze
- Pyro Ball
- Zen Headbutt
- U-turn
- Headbutt
Toxtricity @ Poison Barb / Magnet
Ability: Punk Rock
- Overdrive
- Boomburst
- Sludge Wave
- Volt Switch
Corviknight @ Metal Coat / Sharp Beak
Ability: Unnerve / Pressure
- Brave Bird / Drill Peck
- Body Press
- Iron Head
- Iron Defense / U-turn
Grimmsnarl @ Pixie Plate / Black Glasses
Ability: Prankster
- False Surrender
- Spirit Break / Play Rough
- Thunder Wave
- Brick Break
Runerigus @ Soft Sand / Spell Tag
Ability: Wandering Spirit
- Will-O-Wisp
- Earthquake
- Shadow Claw
- Zen Headbutt / Stone Edge
Dracovish @ Choice Scarf / Choice Band / Mystic Water / Dragon Fang
Ability: Strong Jaw
- Fishious Rend
- Outrage
- Crunch
- Psychic Fangs
It seems like a solid team, I don't think replacements are necessary.
Hope I helped!