
Not sure what you are referring to when you say this for example: "...Just about the only thing shared amongst all the variants is probe and drogue refueling for foreign customers...." ONLY Space retained on the A model for probe/drogue.
Meanwhile this old thread may be useful and of course I reckon this topic has been discussed before in various ways.
F-35A vs B vs C 21 Oct 2015 viewtopic.php?f=55&t=28236