Timeline or not or whatever... its clear this is after the hirako shinji and his gang are exiled together with urahara...... aizen is tracking them in the real world, aizen, gin, tousen replace their ranks, hitsu, matsumoto is in G13 which means its after TBTP arc.... and nothing more... the only thing that is a mystery is the exact years before the bleach storyline.. that is why i said earlier its 100 years to before ichigo was born... that is the only logical and realistic date
I think all this speculation is too difficult to put together, I mean if quincies are supposed to age like humans then how does one explain juha bach? The dude forgot the CC a 1000 years ago so something is definitely off tangent here...not to mention consistency isn't exactly Kubo's forte.
Then again, it all depends on how the time flows in both of these worlds. If time was flowing faster in SS, then naturally, they would need to live longer, in order to match the actual life span of humans living in the real world, so that the circulation of souls would be preserved and balanced. What's more, we don't know if the weight of the soul in human bodies, is the same as those in SS. If the spirits in SS have souls of much greater weight, then this would explain why the quantity of souls in the Human World doesn't affect the balance much, even if they are a few 100?, 1000? times more in HR than in SS.
It's also possible that while the souls are in human bodies, they don't weight/count at all, making the balance disrupted only by hollows + free souls in Human Realm and on the other side, those in the SS.
As far as I know, Souls in SS or HM cannot be in physical bodies, so they have to be spirits. Also Human spirits are reincarnated back to the real world, so I don't think they die in SS unless killed by hollows or shinigami.
Finally, the question I tried to answer related to Juha Bach's age. The answer I came up with was that Juha Bach does not currently have a physical body, so if he ages the same way that shinigami do, he could easily be several hundred years old.