After my first League race last night (Rally League, Spa at Night) 3 of my 4 remaining Multiplayer Achievements unlocked simultaneously.
The 4th (for racing in the rain) unlocked as soon as I did a wet race.
Previously, Leagues did not count towards Multiplayer Achievements and your progress bars would not fill up as a result.
It looks now like any League running you did in the past will count towards your current Achievement progress.
I haven’t unlocked Thru the Pack yet but I suspect that will also be unlockable in Leagues now.
Anyway, just wanted to make this post to let people know incase they were avoiding Leagues due to the Achievement situation.