I find it complicated when addressing to a group. I'm pretty sure that when I use "people" it's plural and when I use "everyone" it's singular then. But I'm confused about the things that come after that.
Here's an example of mine:
1.) People, get your bag/s (assume each person only has one bag) and hit (a) rock/s (assume they all have to hit one rock, not as a team but individually) using your own burger/s! (assume each one has one burger)
2.) What if we change "people" to "everybody"? Would the answers be the same?