Question: Are ego and mind the same?
Mind's imaginations are ego. Actually every thought of the mind is considered as an ego. As long as the mind has thoughts, it cannot go back to the Self. You are that Peace. Your mind is looking for peace and happiness, But it is not in this world - it is in the Self. But the mind simply doesn't know the path. So the Guru guides and tells you what you are really looking for, and inspires you by telling you, "You can do it." and points the way. That is why there is so much importance put on the Guru in the tradition. The famous song of Kabir says that if God and Guru both come and stand in front of you, to whom should you prostrate first. The song itself answers that one should bow to the Guru first, because it is the Guru who has shown you God.
Question: If there is no mind, and the Self itself is Peace, how does ego come in to existence?
Actually it never happened.
So even in Yoga Vasistha, finally at the end it says, "All this that I have said, is an illusion itself - Just experience the Self." This is how the great teachers teach. If they teach too much, then it can just give more imaginations to the mind. More explanations lead to more imaginations, and it creates a vicious cycle. So, do sadhana (spiritual practice).