2x stacking

Hey, been a long time since I've played and I know they've changed some things so just wanted to check, would the 2x buff from the anniversary box stack with a 2x coupon and the 2x event this weekend?

Thanks

They should, buff + coupon + event this weekend.

EDIT: as long as it isn't buff + buff or buff + familiar.

If by "coupon" you mean "cash shop coupon", then yes.