We do not post sources here, for some good reasons.
E2 converts to T, not the other way around!!! hCG will do what your LH should be doing, everything after that is business as usual in most cases.
HPTA restart does not happen routinely. You can do the right things, then see what happens. A SERM challenge will indicate if there is any hope with the pituitary. If that works, then there are specific things to try.