Forum:Achievements and Concurrent playthroughs

I started with a soldier, got to around 33, decided Soldier was boring and tried biotic. Now I find out about these achievements, which explains why my biotic has assault rifles, but brings up some questions.

Do I have to start a new game to receive the award for achievements? e.g., can I finish my Soldier playthrough and have 51-60 unlocked for my Biotic?

And If I get an achievement on my biotic, does the award (if any) also apply to my soldier?