I had something like this but Probe (The Void Hunter Melee) sent a decoy/hologram of you but I removed it as it jumped the Hunter up a good 2% from the others. It was a bit OP with all the other Hunter abilities, and it was a bit too complicated. I had another idea pretty much exactly like yours but featured the Frost Warlock, a dark subclass. Made a bunch of frozen duplicates that all used some freezing move at the same time or just did nothing. I'm not sure about the surround thing but maybe spawning one or two duplicates could work. It's still a bit complicated and I imagine it to be hard to create a friendly AI when there is non in game at this moment. There's a better chance of them being able to summon a stationary figure or somehow summon a fallen NPC.