From top to bottom, you and I are essentially describing the play breaking down in the same way. You've included what I'd consider to be some significant and possibly irrelevant detail. From my perspective, there are also a few inferences which may or may not be correct.
For instance, it's obvious Aho is going for the cycle down low. That's clear as day on tape and everyone dissecting the play will agree with that. If you feel the need to describe those things, that's fine. However, as an opposing example, I don't believe for a second that Slavin places that puck down to Washington's LD side because of any perceived numerical advantage. He looks up, and I'm guessing he sees an open corner and notices Williams is in front, with the shortest path to the puck. Pause the video at 4:30 and have a look for yourself. That play has nothing to do with Ovechkin. It's about the open ice down low and Williams' clear first step. Additionally, at no point can I see Pesce with dominant position in front of Ovechkin because he's out of the frame during the sequence.
I agree it was a bit of a tough puck for Wilson to corral. In my opinion, his mistake was initially trying moving it with his stick for a quick transition play. He should have knocked it down with his skate/leg and been ready to pin it against the boards, letting Backstrom cut back for support. Pinning the puck to the half-wall may have also provided an opportunity for a soft cycle down to the RD. Niskanen had the entire ice and opposition positioning in front of him.
In a nutshell:
Wilson commits an unforced error and is caught out of position, both wide and down low.
Backstrom recognizes this and covers for him because he is in transition to that area. Backstrom commits no errors on the play.
Simultaneously, Ovechkin blows the zone early. If the play unfolded differently, the goal may have been his fault. In this case, it wasn't.
Wilson is now forced to play out of position due to his error. Wilson neglects to tie up McGinn's stick while in the crease.
Game over.
