Pic # 1: This was a new one for me. But that's quite a case of "hat hair", I've never seen pics of him with hair that long. Also, you can see why he grew a mustache later, his top lip is rather thin.
By way of comparison, see this picture of a young Lt. Lee in the uniform of the U.S. Army Corps of Enginers:
http://penelope.uchicago.edu/Thayer/Images/Gazetteer/People/Robert_E_Lee/FREREL*/1/frontispiece.jpg
Pic # 2: The middle picture looks similar to this one, which may be a re-touched picture which is generally credited as having been made about the time of the Mexican-American war:
http://penelope.uchicago.edu/Thayer/E/Gazetteer/People/Robert_E_Lee/FREREL/1/13*.html#image.1
But note the similarity with the following picture of Robert E. Lee taken in Baltimore in 1861 (before the outbreak of the war): He is wearing the uniform of a Col. of Cavalry, but there is a "VA" on the cap, perhaps an alteration made after Virginia seceeded from the Union.
http://penelope.uchicago.edu/Thayer/Images/Gazetteer/People/Robert_E_Lee/FREREL*/1/28/1861_photo.jpg
If the photograph in the original post shows him about the time of the Mexican-American war, he doesn't seem to have aged much in the thirteen years between that war and the outbreak of the Civil War - especially considering he did a couple of years or so as a cavalry commander on the Texas frontier.
Lee was, as you can see, considered quite handsome and when he was posted to duty in New York he became an instant hit and highly-sought guest at the various balls and other social gatherings. I've always thought Tom Selleck would make a great Robert E. Lee in movies, but I suspect we are past that point now, as Selleck is now some fifteen to twenty years older than Lee was at the start of the war.
Of course, Lee managed to age quite rapidly during the first year of the war - his hair turned gray, and he grew his beard out.