All of your posts since Finale night reflect my feelings, so no sense in restating them.
The only thing I would add, was regarding the Kimmel show following the finale (which I only watched yesterday via DVR)........ From Jimmy's perspective this entire series pertained to Jack's journey (life through death). I liked that Mathew Fox agreed with that, even though it was strictly their own personal viewpoints and not necessarily Darlton's. Fox didn't confirm or adamantly agree with everything Jimmy said but he was gracious enough to his host to say "possibly" at some suggestion.
Yes, they were all a part of the island, and we saw each of their life stories play out; but IMO the finale was through Jack's eyes. They gathered for him, to bring him over.
Also, we were told at the beginning of Season 6, that the sideways world was not simply a picking up of their lives as if Oceanic had not crashed on the island. Hence the curve ball on Jack's son. I do think that "if" that was Purgatory, then it was through Jack's perspective.
Interesting, that Mrs Hawking recognized Desmond for the messenger/connector/facilitator that he was, and I have no clue why Daniel and Charlotte (both clearly dead even on the island) were not ready to move on yet........ but I am fine with that.
I must confess that I saw where the finale was heading, and consciously chose to turn off my TV just after Jack and Kate met up at the concert after everyone had left,

so that I could sleep with a happy emotional mind-frame. I watched the remaining portion last night, and while I was a bit disappointed; overall the series was a satisfying investment for me.