You may know more about this than I do, but even the folks at NGA as recently as last summer, which was the last time I was standing by the painting, acknowledge that some dispute whether it is da Vinci's. I certainly lack any expertise to tell. The arguments you make (mostly) are the ones the NGA folks make as they claim it is a da Vinci. I would note that Wiki (not always the greatest authority, but it's handy) says that Ginevra de' Benci is "attributed" to da Vinci while the Mona Lisa was "painted" by da Vinci.
ML/NJ
The exact words are that it is one of 17 paintings attributed to LDV. BTW, for the most part there is nothing wrong with wiki articles, so long as you stay away from political controversy. In fields where I know deeply about the subject the articles are clearly written by well established experts in the field.