Ah, sorry, I forgot that Rhyhorn is not available till postgame.
I was thinking about Hippowden mostly for its Sand Stream ability, but it can be a pain to train, especially with 4 others vying for experience (I really want to use Gliscor as well). I really hate grinding a lot at the end, so I normally keep the party number to four at the most. Tentatively my team is Torterra, Gastrodon, Garchomp and Gliscor, and Hippowden would be a later addition if I chose to use him.
As for fighting, I am going with Infernape, Gallade, and Medicham for sure, but the forth member (if any) is up for grabs.
Thoughts?
I used a Rhyperior for a Challenge, but I was able to trade in an egg, and mine knew EQ, and TFI fangs. It was pretty nice.
If you're like me, and fancy hard hitting moves and OHKOing your opponents, possible movesets would be something like:
Torterra: Razor Leaf/Wood Hammer, EQ, Rock Slide/Stone Edge, Crunch
Gastrodon: Muddy Water/Surf, EQ/Mud Bomb, Ice Beam, Body Slam/whatever
Garchomp: Fire Fang, Dragon Rush/Claw, Iron Tail/Dig/Shadow Claw
Gliscor: Thunder Fang, X Scissor, Aerial Ace, Brick Break
That's 14 out of 17 of the types (15 if you take Shadow Claw over Dig) and the only excluded types are Poison and Psychic. I wouldn't worry about a Hippowdon when you have this kind of coverage...
As for Fighting, I'd have something like:
Infernape: Flamethrower, Close Combat, Earthquake, Rock Slide
Gallade: Psycho Cut, Leaf Blade, Night Slash, Close Combat
Medicham: Thunder Punch, Ice Punch, Shadow Ball, Psychic
Maybe have a Lucario in there? If not, maybe teach someone Iron Tail?
Hope this helps.