That means the person who challenged you has already arranged another friendly match with another team. If it was still an active challenge, it would have remained in your list for you to accept or decline.

Was the game engine reverted back to a pass-favored style? Running seems to do nothing these days.... again?

Lost any tactical advantage I had by doing pre-game scouting. Everything is back at the stage where "who has the better QB wins the game"

How does the training work?
A player needs to reach 100 points in a particular skill to gain a level/point in that skill. Once he gains a level he again starts from 0 plus training points over the 100 from the last level gain.
Each training cycle (once per week) a player gets 10 +- 2 training points automatically, he also gets points from teamwork (teamwork divided by 2), each player also gets gets training points from the coaches skill (For Example: player is training kicking, the coaches skill in kicking is 17 so the player gets additional 17 training points) and lastly he gets 4 additional points for the training hall and 4 for each consecutive training hall upgrade. He also gains/loses points depending on training intensity and players age. And that's the secret of training in Grid-Iron world.

If your coach is 10 in a set of skills does that mean that is only giving a bonus to the player who are under ten?

When do you think a team should hire a coach? After or before having build a training center?