Celestial Servant

[Jolken Jenkins]

Would changing my animal companion into a magical beast through the Celestial Servant feat also modify it's HD and BAB?

[Jeff Merola]

No. It doesn't get anything not explicitly stated by the feat, so while its type is now Magical Beast, it doesn't actually get any of the Magical Beast traits.

[Suma3da]

Jolken Jenkins wrote:

Would changing my animal companion into a magical beast through the Celestial Servant feat also modify it's HD and BAB?

FAQ Source

No, all your companion get is the benefits of the Celestial Template and a type change from Animal to a Magic Beast that's still treated like an animal for certain mechanincs.