Confuciusornis should have had extremely low scapular mobility. The coracoids and scapulae are fused (Chiappe et al. 1999) and the coracoids attach to the sternum at a wide facet. Cats should be on the opposite end of the spectrum.
And indeed, cats have no coracoids to speak of, no clavicles, and no bony connection between the shoulder girdle and the sternum or anything else. The shoulder girdle + forelimb is held only by muscles and, I suppose, ligaments.