Even here in the last part of your letter we find a trace of Aristo’s position, that there are no preferred nor dispreferred indifferents: merely indifferents.
If in one situation we might “prefer” the harder, then the preference isn’t a natural one, as the standard Stoic position states. It’s not merely health, wealth, and high birth: but we might prefer that which trains our souls: the harder.
I intend to write an essay here before too long on Aristo’s position. He was a contemporary of Zeno, and his position was subsumed in the standard Zenoian one.
But maybe, he was right.