So with the update to the BRF missions you need to add traits also to hit 100% Looking at what I had, I have some follower that have the right counters and some slayer traits.
I spreadsheeted it out while I was waiting on Master Plan to update, and now that it has, my math didn't match theirs. When I compared, I found where we went different:
One of my teams uses 2 followers with Orcslayer to hit the 100%. Master Plan only counts the trait once. So far though, everything I've found suggests that you can stack the slayer/environment traits multiple times, like you can with stuff like Burst of Power. I don't have any missions up where I can try adding followers and see if it shows it being applied multiple times though.
I also had believed Dancer behaved this way as well, as it is a trait, which typically stack, and not an ability, which do not once they counter something.
Does anyone know for sure if you can stack multiple Slayer/environmental/Dancer if you get lucky? If I can test before someone can confirm it, I'll add my findings as well, as that may allow people with it at 97% in Master Plan to actually reach 100% without changing anything.
***EDIT***
Go figure, right after I post I go check missions and had one pop. Master Plan is incorrect on this! See below:
Primal is being applied twice, so the Slayer and Environment traits DO stack, unlike MP's current calculations. Still need confirmation on Dancer however.
***2nd Edit***
I've performed a similar test on my only toon with 2 Dancer followers, and Dancer DOES stack until the Danger Zones mechanic is totally countered. In other words, 2 followers with Dancer can fully counter a Danger Zone mechanic just from that.
I've posted about this on the Curse comments so hopefully he can get an update on that soonish.