It's refurbed Maelstrom, yes

I have no idea if it's any good - i suspect probably underwhelming, but still a must do for us! Haha.
you suspect right, it's rather meh
it's just about the same Maelstrom *track* with a Frozen theming, and a picture taken at the end.
If you have young girls in tow, they'll be thrilled. But ... well ... you'll see for yourself.
I woulnd't FP it though, and TBH I have managed to get a 4th FP+ for that one, 2nd week of august last year ...
Regarding FP+ opening time, it's supposed to be midday ... but I'd tell you that MyDisneyExperience is .... well ... just like everything at Disney's ... inconsistent and unpredictable ...
Many have managed to book FP+ earlier. And I myself was able to, a few days ago
we only have
MNSSHP tickets for Aug 25th. I was online at my 60 days mark, and just tried, just in case, at 7am ... and it let me book my FP+ hours in advance ..
so I wouldn't set the alarm and wake up at silly o'clock, but if you can get online once you're normally up, or when you get to the office, just give it a try. You never know