Board Thread:DC's Legends of Tomorrow discussions/@comment-9346948-20160413000408/@comment-3423279-20160414012005

Future Oliver was just Present Oliver with a gravely voice and grey hair dye, plus a few makeup things to cause an aging effect while retaining the body he actually has.

This past Hawkgirl probably stopped caring about her image and body after a time due to Carter's death resulting in her looking different.