As in all simulations in Blender (like rigid body, fluid, fire etc.) you cannot scrub through the timeline (except you baked it) because Blender calculates all values depending on the frame before. So if you don't hit "play animation" on frame 1 - the results might be wrong.

You can copy it as you do it with normal objects in Blender, but you should press the "add spawn instance" button after copying, and then "spawn rigid bodies" to make it work correctly.

yes, i just uploaded quick_spawn_rigid_bodies-1.0.0.zip -> this will work with Blender 5.0