Guild Wars 2

With the current buff if I added a celebration booster will the effects stack?

Yes. Yes they will.

Awesome. One last question.. if I were to also add a MF booster would the magic find effects also stack with the buff + celebration booster for opening champ bags?

Yes. I actually saved up all my bags for this weekend and stacked up 497% MF. Got 21 rares, 3 exotics and an ascended chest. The only ones that don’t stack are Birthday with Celebration since they’re technically the same buff.