Dragonfire Adept - Humanoid Shape invocation

Question

Here is the wording of the Humanoid Shape invocation:

You can assume any humanoid form, as the change shape special ability (MM 306). You can remain in the form for up to 24 hours or until you take a standard action to assume a new form or return to your natural form.

This means, the Dragonfire Adept can turn into any creature that is of type humanoid. I have always thought the Aasimar to be an Outsider, meaning it was an illegal shape for the invocation. However, I have recently discovered that the Aasimar in Forgotten Realms are of type Natural Humanoid, subtype Planetouched.

Does this mean the Aasimar is a legal race for the Humanoid Shape invocation if the game is based in FR?

Answer 1

With no variants

The Forgotten Realms wikia is a strange mix of 3.5 and 4e lore and rules. Notice where it says "For the specific type of aasimar that are corporeal angels, see deva.", aasimar being devas is a D&D 4e concept (and I actually tought they got rid of aasimars).

So, the classification you're seeing is a D&D 4e compliant one.
Consequently, Aasimars are still Outsiders in the 3.5 version of the Forgotten Realms setting* and Humanoid Shape can't morph you into one.

*Forgotten Realms aasimars only differ from the usual aasimars in that they gain the native subtype, meaning they can be resurrected in the material plane as thought as if they were not Outsiders and cannot be banished and the like.

Lesser Planetouched Variant

As @KRyan reminds me, Player’s Guide to Faerûn has variant rules for “lesser” versions of the planetouched races that are Humanoid rather than Outsider.
PGtF stronlgy suggests against mixing regular aasimars and lesser aasimars in the same campaign and the two +2s to ability scores at a +0 LA makes them quite overpowered, leading many DMs to choose not to introduce these lesser versions in their game.
Otherwise, they could be a valid choice for your morphing.

Answer 2

As a GM I have the house rule that "Humanoid" refers only to the shape of the creature. Humanoid then refers to having a human-like shape (one head including neck, one torso, one abdomen, two arms with a joint at the shoulder, elbow, and wrist, two hands, two legs with appropriate locations, and two feet).

However, just because you have the shape/look of something does NOT mean you have the powers of said thing.

For creatures that are outsiders, but meet the requirement of having a humanoid shape the player is able to look like them. Centaurs and their variants (Driders of Faerun coming most prominently to mind) are not humanoid and therefore are outside of this particular spell.