Hellrider kind of contradicts the deck a bit, assuming you plan to make heavy use of Exalted.
I think that mana might be better used making sure that one creature you attack with definitely gets through, and maybe some removal.
Faith's Shield
Spare from Evil
and other such things can help you to get through their army, and protect your guys in a pinch.
I do agree Hellrider seems a bit out of place. With this deck, my ability to use the Exalted mechanic hinges on having Sublime Archangel in play. It's a bit of a shell game. Initially (at least during the first hand), it will seem that I am trying to build a typical Champion deck (play Champion of the Parish and build it up with humans and human tokens). I had Hellrider in there as a way to increase my damage prior to her arrival, for the mid-game, or in case she does not appear.
I do like the cards you suggested. They'd keep my mana curve low. Perhaps an artifact or two? Mask of Avacyn or Swiftfoot Boots?