Please understand that not every time you are quoted is meant to be a direct rebuttal to your statement. Your statement provoked my imagination, and thought happened. My statement was just a continuation (piggyback) off of your's, which I do appreciate
@ask me anything
I did say that this was all a theory. I mean, unless Kubo is shitting on Isshin about having him almost on his deathbed before he meets Masaki (which is possible.... it's Kubo afterall); I'm betting Isshin was Zero squad, he used the Final Getsuga Tenshou losing his shinigami powers, he then is in a confrontation with some hollow, is almost killed and Masaki is the one who saves him. Urahara and Yoruichi, knowing Isshin, transfer some of their reiatsu, along with Masaki and possibly Uryuu's father, allowing him to re-attain his shinigami powers.
It's a theory... an imaginative theory.
On another note, think Kubo will follow up with Ichigo's sister starting to realize some of the family traits?