Which drop buffs stack with which?

Namely:
1) Cassandra's 2x item drop buff (clover/forsythia)
2) Cash Shop 2x drop card
3) Lucky Winter
4) Family rep drop entitlement

Also, please explain how you know that they do or don't.

The latter 3 stack, I don't know if all 4 do.

http://www.southperry.net/showthread.php?t=41180

lucky winter doesn't stack with cassandra's buff