But why did Barry need Devoe's chair when Cecilia could telepathically link his mind to Devoe's?
Because Cecile can only read minds, not project them into each other. Also, it only works with people close to her. She could connect to Barry, but it required using the cerebral inhibitor to interface Cecile's brain with the chair -- which already had a connection to DeVoe's mind -- to allow the connection to DeVoe's mind.
When Barry punched the satellite, I thought he had created a time remnant of himself to help destroy it, but it turned out to be his future daughter.
You could tell by the purple lightning that the second speedster wasn't the Flash.
I will say though that the stuff at the end did feel tacked on, especially Wally's appearance and Nora was almost there as a way of the writers saying, "oh crap, we forgot about this woman, we have 5 minutes left lets stick her in and tease the new season".
That's an odd way of looking at it, considering that every one of Nora's prior appearances (aside from her first at the wedding) has been in a "post-finale" tag scene. So this is just continuing the "Nora shows up in the tag" pattern they've established for the past half-season.
And note that she finally said "This house is bitchin'," and Harry repeated things the Speed Force-addled Barry said in the season premiere. Clearly the writers have had Nora's entire season-long arc planned out from the start. They've spent the entire fourth season seeding the fifth -- anything but a hasty afterthought.
I will say the MVP of the year was Marlize. What a great character she was and the actress did a masterful job all year long. I'm actually going to miss her, considering I don't expect her to show up again. I would be pleasantly surprised if I was wrong though.
I think they let her off way too easy. Even if Marlize redeeemed herself at the end, she's still an accomplice in well over a dozen murders, numerous assaults and thefts, and other crimes. She should have turned herself in to Joe, not just walked away. (But then, these guys have always been too quick to let the people they like get away with crimes. Let's not forget that Harry is still guilty of murdering the Turtle back in season 2.)
Yeah, I think it is a given that Nora pulled a flashpoint and changed the timeline. Seeing time rewind and her joining the fight with Barry the second time makes that clear. No, I don't think Barry died in the first timeline but probably got badly hurt where he was not able to help Nora at some critical junction in the future. That would explain why she went back in time, to help Barry so that he could do something very important in the future but unfortunately she screwed up her own timeline.
Or maybe Barry didn't die, but he failed to stop the satellite crash and it killed many of his friends. Nora's spent months stalking and spying on Team Flash, perhaps for historical research (I'm reminded of the Kristin Wells Superwoman from Elliot S! Maggin's '70s comics), and when the moment of destruction came, she couldn't bear to watch them die.