I feel your pain, experienced everything you are describing when my DD was in 12u. The announcements about attending winter practices or not playing - then the girls that never attended practices start immediately, the promise of roster batting in pool games - that vanished, the obvious playing of certain favorites to the point other parents are questioning why player X is on bench, etc. The list is long.
Best advice- play out the season, work like crazy, improve where you can, and both DD and yourself learn all you can to use in team selection come August tryouts.
I will add that you must truly evaluate your DD and be realistic. We are all our DD's biggest fans, BUT if you think she is the next D1 superstar and she's clearly not, It's going to be a painful process for all. There are teams for all levels of skill, travelling schedules, tourneys, etc. Good luck with your search.