1) Referee Fees: Referee fees are paid according the the age division, not necessarily by the age of the teams. For instance, U-12 teams playing in a U13 division will have to pay the U13 fees ($32 per team). U9 games will only be played with one center ref. Therefore you only have to pay your share of the center refs fees or $12.50 per team.
2) U-12 teams game ball: U-12 teams playing in a U13 bracket will normally be using a size 5 ball. However, if both teams are U12, and both teams agree, they may exercise the option to play with a Size 4 ball. However, the game length and ref fees remain at the U13 level.
3) Normally, it takes 6 teams to make a division, if there are less than 6 teams in an age group, the league will exercise the option to combine it with another age division.. In addition, if there are 12 or more teams in an age division, the league will normally divide that into two divisions based on previous records in an effort to make the games more competitive.