As far as red cards are concerned: yes, they're identical. There are no 'grades' of red; at one end of the spectrum you can be sent off for going in groin high with both feet studs showing, and at the other end you can also get sent off for two petty acts of dissent. And once a red has been...
Exactly right. Unless it was completely the wrong decision the FA, rightly IMO, usually support their referees and have an "umpire's call" view whereby the decision made on the field of play stands. 'Extremely harsh' isn't a good enough reason to get a red overturned - as we all learnt from...