kingCH
Well mate... those essences suck. I mean, for this type of story at least. You want a kingdom building story with a super lord/king slash martial lord slash merchant lord with all that entails? Then stick with the power system that's already there. The essences that he has works for any number of worlds/anime/etc. and their respectively power systems. The options that you post here are completely different, power system upon themselves of VERY specific worlds. If he develops powers resembling that of other anime with the power system already established here then that is another story though.
honestly just slightly buff the existing ones. the grandmaster can see potential already just make it so it can elevate potential (break the 100 limit) or even then if that is not enought the eswseense of blank lets him learn anything right so eventually he can learn to break the limiter. or even as the king he should be able to make his citizens prosper (break the limit) or just a combo of them all. the other ones are to op and might mess up the path of the story or how i imagined it would go. i feel thaT CHANGING OR TRANSFORMING HIS SUBORDINATES would not fit well. (sorry about caps accident)
I don't like bringing in other anime here. They are inappropriate here, do not fit into the existing system of power and will only destroy the plot. if you want to strengthen your mc, then give him some mental strength. Mind reading, battle meditation from Star Wars, absolute memory and accelerated thought processing, hyperintuition, etc.