This is a good example of how communication can effect your team.
I have seen where teams had a full roster in September but the coach did not communicate well or they had uncommitted families and lost players from October to March so they had to plug holes in the roster for spring/summer events.
I also know of teams with 7 in January that merge with another team of 6/7 (and it happens generally this time of year). Sometimes it works out, most times it is a complete disaster.
Teams could be "ok" looking for that number 11 or 12 lady this time of year depending on current roster strength. At 14U and above a team can have a couple involved in school activities that causes them to miss some fall/winter weekend events requiring subs put that on top of a girl or two down and parents could be pushing the panic button if there is not good upfront communication. If you have 10 but you see in fall practices/events that the talent does not match the projected schedule this too can become an issue by the time you get into spring/summer play.
We always did a meet the team night in the beginning of September that laid out the coaching staff, team expectations/goals, roster, fall/winter tournaments/games, projected summer events, fees, fundraisers etc. If its January and you still do not know the majority of your teammates, summer events, fees etc. that is an issue.
It sounds like your coach had the team entered in fall events (that is a plus), do you have an idea of summer schedule? If you are playing in local summer events this opens up the window a little as far as finalizing the roster.
Lots of factors to consider before jumping ship...What type of events is the team looking to compete in? How many players are you lacking? What positions are you looking to fill? Number of quality pitchers?
If you used several guest players for your fall events was the team informed that these ladies may be trying out for the team or were they committed to a team with an off weekend?
I would suggest contacting the HC and inform them of your concerns. If you do not have a good feeling that the coach is being honest with the status of the team it may be time to look elsewhere before you are on the outside looking in or playing a summer where the team is non competitive with a revolving door of players.