All good signs for now, but in my experience, yews collected with heavy chops and root work will look good for the first year or even two throwing out new growth and lots of fine feeder roots. I think they push all that growth from stored energy, and once depleted, they can just give up. I think the guys in Europe have had similar experiences, as they caution not doing much with the tree for two or three years if I remember correctly. So, let the tree rest for a couple of years and get strong again before doing any more major work.