Certain instruments from BFD Percussion don't come out the channel they are assigned to. Shiko Toms, Djembe Toms, Tambourine, and some others come out the Snare channel.
For example, assign the Djembe Toms Tom Floor to the Floor Tom channel and it comes out Snare channel. Setting the output assign doesn't affect anything. The instruments that behave like this can't be mixed. They're all on the same channel with one volume and one pan.
I know this is an old post, and apologies for not getting round to it before. But Percussion now comes with BFD3 Only versions of those kitpieces, which have corrected the channel mapping. Please use those. You may need to re-download and re-install the pack.
They wont be loaded for any existing presets because I didn't want to break backwards compatibility.