@Apollosarcher I think the problem is that unless you severely nerf their capabilities, 7 is just too many. If you look at the clone-based Semblances, they are all significantly simpler than yours. According to what we've seen, Sun is only able to "conjure" two clones, and even then, he has to be standing still to do it. Blake's clones have no ability to strike back. Unless infused with Dust, they are solely used as a distraction. I get that it is thematically appropriate, and it connects to his backstory, but it still is just overpowered. If you are adamant about having 7 clones, then I would suggest perhaps making it so that each one takes a seventh of his whole Aura to be conjured, and when hit, they completely drain him of that seventh. I know you said that it works similar to that, but giving raw numbers actually helps visualize the significance of the Aura drain.
The Dust on the other hand, I'm not too sure about. I do agree with Reap that it would take a lot of time and effort to perfect that craft, and unless he was truly dedicated to the craft, he probably didn't spend a lot of time tinkering with the intricacies of Dust. Keep in mind that Dust is (presumably) a limited resource, and probably not a poor boy's top priority when going shopping. That being said, it is perfectly acceptable for him to know how to imbue thread with Dust. However, the way you have him right now, he is quite a bit overpowered. Being able to just immediately block off an enemy would make for too easy of a fight. If you still want to incorporate Dust-infused thread, then maybe have him carry around a spool or two of thread, which he can throw like a yo-yo to wrap around enemies or something. The thin material would probably translate to relatively weak structures, which, when using earth Dust for example, would mean a smaller rock structure that wouldn't be too hard to break out of. The spool idea also addresses the fact that Bran is able to precisely target any area.
I realize I may come across as trying to take over your character, and I don't mean to do that at all. Just trying to give suggestions on how to balance him out. I think that he'd be a great addition to the RP, so I'm just trying to help out.
Also tl;dr (because that was way longer than I originally intended): Clones still OP, see examples from the show. Dust kinda OP, maybe use spools of thread.