I do not see sickle hocks at all. The second photo shows him standing with his hind feet up underneath him, but surely not a sickle angle to his hocks. I do not see any hint of cow hocks. From the front, one cannot see his hind legs or feet at all. To me, that would indicate that he does not toe out and his hock are not turned in (or we would see them).
I always have thought that 'high' in the withers was good. We have always tried very hard to raise horses that have good withers and hold a saddle well. We fault a lot of reiners and cutters for not having withers.
If this horse uses himself very well and is very broke, I think he is a really nice Ranch Versatility horse. He has the withers and good saddle-back to hold a saddle well to rope and hold a cow.
I do not know how close he is to Lenas Sugarman, but he was a pretty nice horse showing and winning in both the NCHA and the NRHA and sired cutters, reiners and reined cowhorses.