MLP depicts pets one way, other shows do it another way. Different shows, different rules. Since EqG is an MLP spinoff, it stands to reason that it will probably emulate MLP rules more closely than some other unconnected show.
Thing is, is Winona going to be in EqG? If so, she'll either have to be elevated to a speaking roll like Spike, or he'll have to be reduced to a non-speaking or at least subservient roll like her, or they'll end up with some dogs that can talk and some that can't. Not that they couldn't do that (Family guy does it), but IMHO, you end up with something that doesn't smell right any way you cut it.