What's Going On In This Soccer Sequence

Note that the Orlando player (in purple) just … lays down behind his teammates even as the play is taking shape. He remains on the ground until the ball has left his opponent’s foot. Is there some strategic reason for his, or is this an extended flop based on the hope that the ref would notice?

I think the strategy is that the players in “the wall” are going to jump to try and block the direct shot, but if the striker hits it low they might in effect jump over the ball. By lying down behind the wall that possibility is prevented.

^^

That’s it. Note that this doesn’t happen in mid-game, but before a free kick. It used to be a tactic to kick the ball low, almost ground level, to out-trick the players in the wall who usually expect a high kick and automatically jump up to clear the ball with a header. That’s a good strategy because the goalie also expects a high kick, and only sees the ball at the last moment which makes it hard to react in time. A few years ago, you first saw that tactic of a defender laying down behind the wall to prevent that. I don’t know who came up with it first.

It started in Brazil league play.

Yes it’s this, it’s quite common for the striker to judge that the players in the wall are going to jump up, so he might consider sliding the ball underneath them. Lying down behind them is a risky strategy though, as the ball might hit the player’s arm, and then they’ll be looking at a penalty. It’s why he’s facing away from the direction of the ball, to mitigate this risk.