Inexpensive legal options could be the strata plan taking out a small debt summons against the offenders and paying a filing fee, currently $105 in NSW which gets added onto the debt owing. You haven’t said what state you reside in but it can be done online….. or rocking up to the local court house and filling out a form as long as you have a current address(s) to serve it on. Have an executive committee meeting to vote on this course of action before doing so. You can pursue it yourself instead of paying a solicitor or credit recovery business to do it for you. Solicitors legal costs can also be added onto the judgment debt if you prefer to engage a lawyer.
Make an inquiry from the insurance company re excess and premiums. It may be better time wise to have someone else do the recovery work for you despite the costs. After all, it sounds like you are going to be the person responsible for doing all of the legwork and the associated hassles if you have an apathetic committee as a counterpart.