I'm not fond of Iron Will for these critters, but I love all the rest.
Updated.
How about Weapon Focus (bite) for the other feat (like a wolf)?
Yeah, Multiattack makes the best sense. The bite does work better as primary.
Updated.
Environment: See text?
Organization: Solitary or team (2-x)
Challenge Rating: 3?
Advancement: x
Well the original would suggest "Any land" but we could make it "Any land with temples of St. Cuthbert" ?
I'd think "Domesticated" like SRD horses and dogs would make more sense.
5-8 HD (Medium)? Ironically enough I don't fancy Advancing them to Large. Maybe 5-6 HD (Medium) like the Medium-sized range of a Shadow Mastiff.
Let's split the difference with "Any land (see text)". I like to follow the standard presentation and not put really specific locales on the Environment line.
Are we finished here?