Do Demon Hunter sentries benefit from Big Bad Voodoo?
Solution 1:
Sentries are definitely counted as pets. So they will get boosted by Big Bad Voodoo if they are within its range.
However, if you are thinking of the Marauder 4p bonus that fires your attacks, those attacks are not counted as part of your pets. They are counted as YOUR own attacks and will get any bonuses that you do, including that of Big Bad Voodoo. So for that to happen, YOU will need to be within BBV's range for those attacks to be boosted.