Is it possible to find the name/info/stats of the player you're currently playing against on the starcraft2 ladder VIA api or webhook? Lets say in the case of a barcode, where you visually don't even know.

yes, there is a web server on the game client that contains an endpoint that gives you your current matchup. You can use that to query the web api to get some info on that player.

Right, but that's not quite accurate right? Player names for starcraft2 aren't unique, so how do you know who to querry for? Lets say in the case of the barcode llllllllllll?

I'm assuming your talking about this:
http://localhost:6119/game