Lovely. For anyone wondering he'll be following
this ascension path, in terms of initial powers anyway, as he develops more. First he has to unite his astral and physical bodies though, else true progress cannot be made since the two are opposite sides of the same existential coin.
Of course that requires he master both individually. He's already largely done that with his physical body, becoming low-level superhuman in nature, so that just leaves the astral. Then the uniting, which is where he'll technically attain the powers presented in the Third Initiation.
EDIT: As far as the eight Siddhi of the Fourth Initiation, well it'll be these more or less. I say more or less because obviously there will be limitations and such given the nature of MR. Plus he won't get them all at once obviously, since even though he has the potential he must spend the time and effort to attain mastery.
- Aṇimā: the ability to become smaller than the smallest, reducing one's body to the size of an atom or even become invisible.
- Mahimā: the ability to become infinitely large, expanding one's body to an infinitely large size.
- Laghimā: the ability to become weightless or lighter than air.
- Prāpti: the ability to instantaneously travel or be anywhere at will.
- Prākāmya: the ability to achieve or realize whatever one desires.
- Īśiṭva: the ability to control nature, individuals, organisms, etc. Supremacy over nature and ability to force influence upon anyone.
- Vaśiṭva: the ability to control all material elements or natural forces.
- Garimā (per the Rāmānanda Sampradāya): the ability to become infinitely heavy and be immovable by anyone or anything.