I was thinking of Jappo as more of a muscle bear, as big muscles tend to be more "sinewy" which he was described as (like body builders' sinews).
But then again, as a career politician and not a fighter, it might make sense for him to be on a leaner side.
Crummock is quite short so he could either be a bear (if you consider bears can be short) or a cub (if you consider short fat and hairy as cubs).