ABs vary depending on how much offense in that game. Every player is in the batting order, first game is usually 10 innings and the hitter that was on deck when the first game ended leads off the next game. Typically players would get a minimum of 2 ABs in each of two games if the pitching dominates. 6 ABs during the showcase would be average. It is possible there could be less or more. Of course there is also batting practice and Diamond Kenetic testing. Also the weather can cause some changes.
Players play most of the innings. Primary position as much as possible. Some switching of positions can be necessary at some events. Typically shortstops should be prepared to play SS, 2B, and 3B. Obviously outfielders all three spots. Some catchers could play 1B for a few innings.
Hope that helps a little