Which umpire?

Question
Mark,

In a men's slowpitch softball game with two umpires, which umpire is responsible for watching the catch on a flyball to the outfiel and which is responsible for watching the tag up by the runner?  The situation we had was with a runner on second.

Also, we play with ten fielders and two of our players were running late and still in the dugout when the first pitch was thrown.  After the first pitch, they came onto the field for the rest of the top of the first inning.  When we were up to bat in the bottom half, one of the players who was running late was due to bat second and the umpire said he cannot and would be called out unless the two men running late batted at the end of the lineup since they were not on the field when the first pitch was thrown.  Is this accurate?

Answer
The home plate umpire calls the catch and lead runner on the tag.

Those players listed in the line up would be out if they did not bat in their listed place on the line up.  Once the game starts the line up can not be changed except for legal subs.

Tom