This is the type of topic that really needs to be addressed by a qualified attorney, but Mike hit on what I understand to be two very critical points, those of employee versus independent contractor and license versus ownership.
'Work for hire' and copyrights can be a
bit more complex for independent contractors as while generally all rights lie with the creator(s), certain types of work by independent contractors, some of which could fall within the scope of your situation, could be considered as 'work for hire'. However, there are specific conditions that must apply for the work of an indepeendent contractor to be considered 'work for hire' and one of those is an agreement by all parties involved to the work being 'work for hire'.
On the other
hand, if you are an employee then in a very simplified interpretation, anything you develop as part of your work is likely considered 'work for hire' and all rights belong to your employer unless you have an employment agreement that specifically states otherwise. So if you create light plots, scenic design,
call sheets,
cue sheets, original music, scores,
etc. as part of your work
role for an employer then those likely belong to them.
Related to this is the issue of when work can or cannot be considered that of an independent contractor. Does the school or
venue control when you work or how you perform the work? Did you use any of their equipment or tools perhaps including any 'educational use' licensed software? It can be quite easy for work or services performed to not meet the requirements for being that of an independent contractor and to be considered to be an employee/employer relationship rather than a contractor/client relationship, and thus inherently 'work for hire' unless otherwise defined.
As Mike noted, I find that many people ask for ownership since that makes it easy for them but what they often really require is simply some form of license. Unfortunately, when dealing with government agencies or large corporations they may agree but still be unwilling or unable to deviate from their standard terms and conditions.