If the coop is kept bone-dry, the ventilation is generous, the bedding well-managed, and the chickens are not overcrowded there shouldn't be any noticeable odor except under unusual conditions.
I forget if I already linked you my article on Deep Bedding or not so I'm sorry if I'm repeating...
Rules of thumb:
If it looks like a dollhouse it's only suited for toy chickens.
If they don't list the actual dimensions on the website it's because they're trying to make you think it's bigger than it is.
If there are more nestboxes than the number of chickens it ought to hold there are...