Since WWE has already disregard Taker/HHH @ WM 17, are they going to erase that match from history also?

Probably not, they are just not mentioning it to make the feud better. Probably after the whole feud they'll just randomly start mentioning it again. Ridiculous by WWE, they could say like Triple H has tried once and failed he won't make the same mistake again or something better to build up the feud.