Taking my earlier spec and adding it to your thoughts and the additional vidcaps, here is what I come up with, there are 3 parts of this challenge:
There are 5 bags of puzzle pieces hanging on hooks out on a platform in the ocean. You can see them hanging here:
Each of the wake boarders will go one at a time and grab a wake board that is tied to a rope that is attached to a big reel that 4 tribe mates will spin to pull them and the bag of puzzle pieces in.
Ozzy with the wake board running out to the platform:
Here in the background you can see the vertical puzzle platform with 5 vertical empty slots:
You can see that Ozzy are with the wake board and puzzle pieces here:
Here is Coach and Edna's hands at the top of the vertical puzzle with a hook to pull up the bag:
Whitney with a piece of puzzle (from the intro promo but it matches this challenge):
Vidcap evidence of wake boarders:
Blue Upolu: Albert, Brandon, Mikayla
Red Savaii: Ozzy, ???, Dawn
Vidcap evidence of reelers:
Blue Upolu: Albert, Stacy, Sophie, Rick
Red Savaii: Keith, Cochran, Pappa Bear, Jim
Vidcap evidence of the puzzle people:
Blue Upolu: Coach and Edna
Red Savaii: Whitney and ???
Missing from vidcaps: Elyse
So we know that Albert pulls double duty for Upolu as both a reeler and a wake boarder, but we don't know for sure who from Savii doubles up. That being said, Keith is the only reeler dressed in shorts and even looks like he could do both.
It is also safe to assume that Elyse is on the upper puzzle station with Whitney.
I think that when Ozzy loses his wake board he will have to scramble to get it and go back to the start because here in this sequence we see him in a lane all by himself and there are 2 bags left on the hooks:
This is an early challenge shot as you can see Dawn and Brandon patiently waiting but not looking too stressed out:
But here you see Dawn with the 2nd to last bag:
And here you see her exhausted:
Note also in that vidcap that they are now reeling in the last puzzle bag (because Dawn got the 2nd to last bag) and there isn't much rope reeled in yet, so they just started to reel.
At this point we don't see anything in place for Upolu on the vertical puzzle in the background. Or maybe they put the 5 pieces into place and it drops a flag down the front of the vertical face, but it certainly looks like something goes there.
I don't know why Upolu would have Coach up on the platform, does his tribe think they need his strength in lifting up the pieces? He proved in the first and 2nd challenge that he wasn't good at puzzles.
Also, why is Cochran on the reel instead of up on the platform to do the puzzle? Upolu had 2 women on the reel, Whitney could have done that part and have Cochran the puzzle man up above.
Is it possible that the rules are that 1 man and 1 woman minimum need to be on the wake board stage and that Savaii chooses to go Ozzy, Dawn, Ozzy, Dawn, Ozzy. That keeps the same 4 reelers throughout.
Whereas Upolu decides to rotate Brandon, Albert, Mikayla, Brandon, Mikayla (based on background pictures of shoes, shorts, and guessed timeline)
Also, it appears that there will only be one combined RC/IC again since there will be an RI duel. I give the edge to Upolu winning this.
I'm not sure who came first hosting games, you or Tribe, but you are both nefarious! - CTGirl