Physical XP I assume works somewhat similar to XI did in that groups get a share based on the kill, with level adjustments made to the XP earned. I have limited experience of this but based on a handful of observations Id surmise that this is the case.
Class XP seems to be a free for all though. If player A spanks the mob and gets 1000 class XP, and player B sits on his **** and does nothing (or oppositely and maddeningly, is altruistic and does nothing but heals) and gets 0 class XP, at the end of the fight A gets 1000 and B gets 0. It isn't shared.
Conjurers casting heal do get exp. In fact, we tested this out in a balanced 6 man camp party and I was getting more exp spamming aoe heals than attacking the mod. This was not the case in beta but is fixed no so no altruism involved. Conjurers are rewarded for playing their class as a healer should be paid.
That was until right now - not sure but I think we might be about to get hit with the nerf bat in the current emergency maintenence.
FFXIV: Crafty Hallie, Ultros