Theosophy, esoteric Buddhism, and Hindu sects like the Vedantists come at several points of contact quite close to the Hidden Teaching, but diverge at others. The septenary constitution of man is somewhat theoretical--as actually there are only two entities, the ego and the Overself--but it may be useful for analytic purposes.
Your understanding of different ways in which I use the word ego, and in which Theosophy uses it, is correct. What happens metaphysically to the further existence of the being resulting from the conscious union of the ego with the Overself is guarded as a mystery, and may not be discussed.
Those who call Madame Blavatsky an unmitigated quack are talking nonsense. Although her teachings were partly unreliable, there was nevertheless a great deal of truth in them; and although she herself was imperfect, and occasionally unreliable, she was mostly sincere.
-- Notebooks Category 12: Reflections > Chapter 5: The Literary Work > # 240