Changelings are my mostest favorite race ever.
However I'm not sure about giving them natural armor or claw attacks.
I like warforged too, but I'd suggest to give them the option of the composite plating (with dex/skill/spell numbers) or nothing and just buy normal armor. Or make armor available to them at an enhanced cost, give them some kind of bonus and make it un-take-offable as they upgrade their bodies. I saw the mithral feat but didn't see the other one.
The thought process behind giving Changelings the options of those traits/feats was twofold. First, they came from Paizo's version of the Changeling, which is far and away a different beast than the one found in Eberron. Second, and the stronger of the two, those traits/feats were a nod to the Changeling's Doppelganger heritage. Similar in idea to how Warforged were given the option of developing into a more construct archetype (e.g., The Lord of Blades) or biological one.
When it came to the Warforged I honestly hated how WOTC approached them. Not only did I feel that they were too restrictive to the martial classes but imo having to burn a feat for adamantine body and the like seemed like a huge waste during character creation. Looking through the Races of Eberron book I found something that I liked, the "Unarmored Body" feat (page 120). Drawing from it while tweaking their basic racial bonuses (e.g., retaining the +2 natural armor bonus) I felt that I had hit a nice middle ground between flavor and player options.