Can someone tell me the exact modifiers for group play?

I can't seem to find anywhere exactly what they are. For example, % more / increased monster life? % increased currency drops? % increased waystone drops? Etc..

And do they continue to apply after one player has left / died?

Thanks

X2 hp/dmg/loot each player. You have to be in the same area , if someone left i think bonuses/difficulty still work