Yes, you can have multiple characters in the same Spine project and edit their individual positions at runtime without affecting their animations. Each character can be a separate skeleton within the same project, and you can control their positions independently by adjusting the root bone position for each skeleton. This allows you to move them around as needed while keeping their animations intact. Just ensure that each skeleton's root bone is positioned correctly relative to where you want them to appear in your scene.

You can create multiple skeletons in a project. They are completely separate.

If you create a single skeleton, you can have multiple characters in it by parenting them to a new bone per character under the root bone. You can move any bone around at runtime, so of course you can move those bones too.