Nifswapping is swapping your Leaderhead's nif structure with the original model's. From what I understand, importing into Blender ruins the structure, so you need to swap it with the vanilla lh to fix it. Iirc, there should be something in Ekmek's tutorial. If not, look in the last 5 or 6 pages of his tutorial thread, since Capo had questions that taught me how to do it.
As far as the Icons go, what I think you mean are buttons. Those have nothing to do with nifswapping but you must not have done the alpha channel correctly or something along those lines.