I think their more cats, except Suicune. Maybe they're cat/dog hybrids? My fav in order would be Suicune (who is think is femine because of it's mane), Raikou, then Entei (Entei should belong to Molly and Suicune should belong to Ash. Seriously Ash is the only one Suicune allowed to ride more then once).
I personally love Raikou the best I guess cuase I love Sabor-tooth tigers(not saying hes a cat, just saying I like the big teeth) and Ecetric pokemon are my secound favorite type(first being fire) ^^ So Raikou just seems like both combined, besides I love the zigzag stripes too