Obviously our best bet is for Sophistication, the role, to tell us who the leader is, since technically the narrative and OP states that the Federation is "ruthless" and is the de facto bad team. If we kill the ??? leader, there'd be an easy win.
We also need to be careful for those third party roles. Who even knows what Epoch does.
Can we kill the leader just by lynching though? If 'Sophistication' reveals the leader, they'd also be revealing themselves.