Actually 3-0 makes it interesting as then they would be -26 and bumpy/villa -27. they have to lose the last game, so even 1-0 loss would put them on -27 and bompey/villa need to win and even 1-0 would put them on -26 Ignoring Villa have 2 games though
Goals scored if GD is level (eg finishing on -27). And Watford are behind Bmouth and Villa on that. Barring some weird result where Watford lose 5-4 to Arsenal, this 2-0 is enough for Bmouth. But Villa need one more, to cover a potential one goal loss tonight (or two more to cover a two goal loss, etc).
I got 11-1 on Bmouth to stay up, after we beat them. I'm still not sure if they will, but those seemed like crazy good odds.