Can the ego be channeled within any level of the mind? Would that be advantageous for doing trauma resolution?

The ego can indeed be channeled within any level of the mind. This has the same pros and cons as dealing with those other levels of the mind themselves, that to do so for the conscious level or the upper subconscious would be perceived and felt as intrusive. And while that can be done, there is no direct advantage in doing it via channeling to those upper regions, compared to working directly with the client. So the same would pertain to looking and engaging with the ego selectively. It would have the greatest utility done within the deep subconscious. In practice, at each level of the mind, the ego component will be interacting and present. And that you can count on because its job is to be on the front lines of anything happening, to maintain individual and speak up and speak out if there is something needing its services. So it will not really need to be engaged with directly and purposefully as an object of a therapeutic session. Even in situations where you are dealing with severe narcissism, to reach out to the ego is redundant because it is the ego controlling things and running the person's life. So any outreach to do trauma resolution will engage with that part of the mind by default.