can we get everyone together?
If you pay people, they will show up on time and be professional. If there is no pay, you get what you get.
If one of your cast or crew members doesn’t show up, you should always have a fall-back plan, so you’re not holding up or have to reschedule the production.
You need to respect everyone else’s time and realize they always could be somewhere else. Even if they’re being paid, unless you’re offering full industry rate with overtime, people are only there to do a job. If you disrespect them or treat them like garbage, they can easily walk off set and you will have to take on the responsibility or find someone else who can.