That was a really nice write-up, well done!
I am behind on The Flash but remain faithful, last night was the debut of 'Welcome to Earth-Two' in my area, we are unusually well behind for some reason but I have to say I thoroughy enjoyed the episode and in particular the whole design ethos of this alternate world - this is what Parallel earth stories should be like, and why Earth-2 has always had a strong appeal in the comics.
Regarding your 'Trajectory' assessment - I confess the CW synopsis didn't leave me expecting anything more than a filler episode, so to get so much movement on the Zoom plot is a great surprise and most welcome, as the mystery had begun to plod a little and feel too drawn out.
Based on these reveals it does seem likely Zoom is to be a desperate Hunter Zolomon, using the captive Jay Garrick as a battery? It does add a convincing layer to the character and his menace that he is in fact an addict, literally dying for his next fix of speed. I had wondered if the blue lightning that hallmarked Zoom might be significant but this is an unexpected and logical means to explain its significance. Now if only they would explain Reverse-Flash's red signature...
Reverse Flash being red: well as he puts it:
"everything the Flash is, I am the REVERSE of"
he is so intent on being the direct opposite of the Flash that perhaps through will power he has altered the color of his lightning. Just speculation.
As to the blue lightning....I at first attributed it to being on the "dark side" of the speed force as it were. Now however blue lightning appears to be associated with burn out and self destruction.
Could Barry go fast enough to turn blue and disintegrate....well the newspaper of 2024 states he vanishes during the red sky event. He could end up going out the way he did back in Crisis #8.