Hi, I'm a U.S.-based Wordpress/PHP developer, and envision your project as perfectly suited to implementation as a Wordpress Plugin. As you probably know, Wordpress powers more than 1/3 of all websites on the internet today, from simple blogs to the corporate websites of global brands. Your own website is probably already running Wordpress, and ready for easy installation of this plugin.
1. The Wordpress system will manage admin/users of different levels with a robust and secure login system, easy upgrades, and even the ability to host your own website of any type in the future, with ongoing security patches and a millions-strong community of developers keeping it safe and secure.
2. I would extend this system with a custom-made plugin to extend the functionality to manage your specific business data, to get your work done, with the specific views and dashboards you require, including all of the following:
3. User configuration: configure new users in just a few seconds, add the vital information needed for their user/employee/banking records, work availability, etc, as described, with a Settings panel, Some screenshots are attached with similar "Settings Panels" developed for other similar projects for web applications.
4. Show calendar, for visual feedback on shows scheduled.
5. Expense reporting and job assignment features as described.
6. Data export functions for generating spreadsheets for payroll, billing reconciliation, expense reimbursement, etc.