"1. Yes, we know that "all had something to say about Sinosauropteryx."
However, they were smart enough to realize visual analysis does NOT qualify as conclusive evidence."
The paper that you cite is based on exactly that - visual evidence alone. That analysis is of questionable quality and consistency.
The study is far from conclusive. It does not address the structures that are not along the midline of Sinosuaropteryx at all. Each of the four specimens shows these structures. They appear on many parts of the body. This does not conform to the analysis of Feduccia, Lingham-Soliar, and Hinchliffe. They have put forth a hypothesis that they have not adequately supported and does not effectively address all of the evidence.
"There had been claims that the supposed feathers of the Chinese fossils were a preservation artifact. Actually they have roughly the same appearance as those of birds fossilized in the same locality, so there is no serious reason to think they are of different nature; moreover, no non-theropod fossil from the same site shows such an artifact, but sometimes show unambiguous hair (some mammals) or scales (some reptiles)."