If I were MCing this situation, I would say Merciless/Bloodcrazed is in effect if you are leading the gang and fighting alongside them, yes.
If you send them off to do your bidding and fight somebody, then no, definitely not. You are not there, so they have to make do with how they do things.
If you are leading them and directing their attacks on the battlefield, but not actually fighting yourself, then it would be up to the role-playing, I think. Like, if you are bloodcrazed and your leadership consists of you yelling at your gang to "kill kill killlllllllllllllll!!" and "drink their blood!" or something, then sure, your gang can do +1 harm.
But if they are besieging a compound over the course of many hours and you are observing, giving directions, organizing the supply chain, all that stuff, then no +1, you're too busy to make sure they are as Merciless/Bloodcrazed as you are.