I want to express my very own, personal, subjective opinion on that case.
I'd say that point "3. Paste layer, Paste everything." is great.
It can be a user-friendly "quick and dirty" way to use canvas.
I, as a user, would even be ok with some limitations (like maximum caption area size available).
If one wants to make some serious big canvas usage, with it being game's core mechanic - go ahead with adding it's containts object by object. If another one wants smaller scale episodical usage of it then something like "copy paste everything within set area fast" would be nice.
Other points like rotations, arcs, resizing etc are secondary for a quick and easy use.
Maybe the "Load image from URL" point can be also usefull, to a limit.