On the subject of Brain in warden armor, it might not be as ridiculous as you think. Machinists are physically weak, so the armor would be largely self-powering. With enough telekinetic skill he could probably simulate the effects of a pilot inside the armor (provided he can do Telekinesis without his body). Sure i t will drain his power points quickly, and while he's doing that he probably can't use other Psionic powers, but it's an explination.