Eckhart Tolle has a bit of a different definition. He calls us all consciousness, but it is all trapped in the form of identification with thoughts, beliefs, emotions, etc. The start of enlightenment is the slow removal of consciousness from all these forms, and letting just be pure consciousness, which he calls presence. He doesn't explicitly say so, but I get the idea once we withdraw consciousness (or energy or whatever you want to call it) from all our thought forms (such as the ego), that is awakening.
Well, the way I use the word consciousness is that it is the same as the content it contains. There is no consciousness if there has been no experience, no memory, no thought, etc. Those things ARE consciousness.
These things accumulate over time, and that is the pool that one draws from. So, if there is no content, then there is no consciousness, because the content IS the consciousness. (You will hear J. Krishnamurti talk about this quite a bit. He speaks of it as a container AND the contained.)
Can the ego be here without consciousness? If we say the ego is the self, the center, or whatever, then it must be built from something. This ego is a part of consciousness.
Is there a start to enlightenment? I take it to mean that enlightenment takes time. If that is the case, is that enlightenment? Does wholeness require any time? One might say it takes time to get there, but where does one have to go? How long does it take to move from zero to zero?
Can consciousness be removed? It isn't a matter of removing anything. It is more like seeing what is there for what it is. I'll give you an example from my own life if I may:
I noticed that after this realization, I seemed to have lost so many memories. It was what I imagined amnesia to be like. But I later came to understand that the memories (the consciousness) are still there, but since there is no self to be emotionally involved, they are not present.
The self is linked to many events that solidify its existence. I was beaten, I was robbed, I am good at sex, I am stupid because of an event, I am better than others because of this or that, etc. These things become important and solidify what we consider the self to be. These feelings of who we are define the things that we do and the things that we say. And it all comes from what has happened before (the past).
Now, if the self is gone, there are no longer important connections to what has happened before. Since there is no self to define, the definitions (the past) become useless. The definitions are still there, but there is no connection.
Maybe it is like having a phone book; it is filled with numbers, but you do not know what is there unless you need a number. Unless you look. Otherwise, it is just there, causing no harm to anyone.
That is as close as I can get to it in words.