Nice job on whoever tattooed this but the one on the right needs a little bit more sharpening up. The left tatt is fine except for what the other people below have mentioned. The right tatt lacks quality, almost as if the artist got tired throughout the tattooing.
generally yes, but with this design, they are mostly just facing out toward the viewer, and the body shape of the subjects flow better with the shoulder blades in this way. Mirroring the design would be counter-flowing & not as strong.