Ok, I read all of it (I have no life)...
I think that Ichigo had his hollow since birth as he have this huge reiatsu, but wchigo could come out just after Ichigo became shinigami on his own...
Ichigo is diffrent from any hybrid as he's maing character and he must be super special to win all those fights that there still be
Spoiler for my theory with manga source:
it might be that Urahara created Ichigo, and that why he's perfect
it's because Isshin knows Urahara and he always treat Ichigo diffrent, and he told him that his name means to protect, he was ment to grow in to a good person and strong fighter, with all those fights with his father
as for naming swords... if u won't threat ur sword as a tool and care about it more it won't get rusty and u can rely on it more, be more confident and put more skills in weilding it
...
as for Zangetsu... he wants Ichigo to be strong even if he had to ask Wichigo to help in trying, and the reason why he didn't explain how it was to ichigo was because:
1)if he told Ichigo that he has a hollow side and it want to take over him, Ichigo probably would stop trying to be stronger right there, and after he reached BanKai he must traing more just so Wichigo won't come out again
2)that's the way Zangetsu is (he's old dude with beard because he's cool that way)