Remakes actually don't effect the MMR of the dc'd player
http://euw.op.gg/summoner/userName=Armonius
Started with 2W/8L placements, got in bronze 1.
Currently 31W/123L (~100 of the loses are remakes, where I was the dc'd player). I still gain +25lp for a win, -15lp for a lose and I am still in bronze 3 after 100 more loses than wins.
Pretty sure Riot lied when they said it counts as normal lose, it doesn't seem to effect MMR. Furthermore I had ~20 remakes on bronze 3 0lp, still no demote. After that I lost a game normally, still no demote.