I haven't looked at your martial maneuvers yet.

Fluff: What is the fey dream? I don't see any 'dread aura' in the abilities.

Armor Mastery. What is that? Is it just treating medium (and heavy) armor as light armor? Or 1 category lighter? Given that the character already gets all armor proficiencies, the only real benefit seems to be the reduced movement penalties. Unless this ability is intended specifically to support a gestalt character of some sort?
Agile weapon mastery. Seems straight forward, another form of Shadowblade.
Agile armor. Seems a very dippable ability. +2, then +4. Then nothing.
Regaining Maneuvers process is odd. It seems even more forced than the Crusader. There's no requirements to it beyond "don't use a maneuver." Swordsages meditate wtih a fullround action to regain one maneuver. Warblades spend a swift action making a standard attack (or a flourish as a standard) to recover all maneuvers. Given that the wildwood can use all his actions via spells/attacks and still regain maneuvers, it seems much more powerful than the standard.
Forgot to bold the Healing Dreams entry.
Champion of Summer/Winter. I assume you envision the courts at war? In that case, the Champion of Summer is significantly more powerful than the Champion of Winter. He's specifically immune to everything the Champion of Winter can do.
--Champ of Winter probably needs to be beefed up in what they can do. Or they get an exception that lets them match the champ of summer. Even a 50/50 chance.

I do think the summer/winter should be chosen earlier in the class. Perhaps minor abilities throughout the 20 levels to illustrate the difference. Or some of the Star Dream maneuvers have different effects depending on what court the knight serves.