Mostly wrong
D'ivers are just another form of Soletaken, really. They're, as far as we know, all humanoid, but while Soletaken can semble into a form of an animal (as far as we know, just one form - they can't change into others), D'ivers can semble into many versions of the same animal. Again, the animal doesn't vary for each D'ivers. The wolves hunting Icarium and Mappo in Deadhouse gates was a d'ivers, as were the Dhenrabi Fiddler had to fire a cusser at. Urm... oh yeah, plus the "merchant" that guided Felisin Heboric and Baundin for a while - he was a D'ivers rat(s) called Gryllen, iirc.
But yeah, they're basically two kinds of shapeshifter. D'ivers are generally more powerful, for obvious numerical advantage. On the other hand, shapeshifting certainly seems to affect the person's mind - most of them are insane, and always stay in their animal forms - d'ivers are affected by this significantly more than soletaken, hence the impression maybe that they don't change...