To create multiple copies of the same character with slight variations in animation, you can use a combination of techniques in Spine. First, ensure your character is set up with a skeleton and meshes, as you mentioned. You can duplicate the character's skeleton and animations within the same project. Use the BoneFollower component in Unity to attach sprites to the skeleton's bones, allowing you to create multiple instances of the character. For variations like different eye blinking times, you can offset the keyframes for specific animations such as blinking. This can be done by duplicating the animation and adjusting the timing of the keyframes for each instance. Additionally, you can use the Key Offset feature in the Dopesheet to create a wave effect for the crowd's movement, giving each character a slightly different motion.

Create a single skeleton with various animations. At runtime, load the skeleton data once, then create many skeleton instances. Play different animations on each skeleton instance and position them to make a crowd.

If you want to do it all in an animation, you can make one crowd member, then duplicate and move them to make a crowd.

@FiM With spine-unity, you could use the RenderExistingMesh example component to render duplicates of an existing skeleton in a cheap way, without animation or mesh-generation overhead. This way you could create 10 skeletons which animate independently, blinking and waving at different times, and create 10 duplicates of each of those 10 skeletons to get a crowd of 100.

You might also want to check out the Spine Examples/Other Examples/FixedTimestepUpdates example scene which demonstrates updating skeletons e.g. every second or N-th frame only, reducing the animation overhead even further.