Emboar has the best diversity out of all the starters, so I'd use him.
The monkeys have solid diversity as well, but they might be a bit frail. They are a good choice for someone with an offensive style.
Archeops has a huge Attack, and with the ability to learn several different type moves.
Carracosta has great Defense, and has solid moves as well.
You can only choose one of these, and I would choose Archen if I were in your situation.
Druddigon is solid, not as good as the other two Dragon types but since you don't want to use Haxorus and Zweilous evolves at Level 64, I'd choose him for a Dragon type slot.
Chandelure has the highest Special Attack of any non-Legendary Pokemon, and he'll make a great addition.
Stoutland can learn all of the Fang moves (Thunder Fang, Fire Fang and Ice Fang)