It is all based on the matchups. The Big XII was facing several matchups with the Big East in bowl games including the BCS bowl we are tied to. Typically the Big XII was getting matchups with the best teams the Big East has to offer. On the other hand most of these other conferences were able to pick and choose which Big East teams they got to play against or had bowl tie ins against the mid to lower level teams in the Big East. This is another reason conference records against other conferences are not a good indicator of conference strength. It all depends on the overall strength of the teams played and the strength of the team playing them. A simple win/loss record doesn't come close to telling you the entire story.
Agreed.
And yes, pretty sure all three had started ACC play by 2005.