No you are absolutely not annoying anybody – great you have these requests!
Well the issue with source-changing is, that it is not supported to change the source at the moment 😉
The better approach would be, to create different variationTypes of an EntityBase where each one has its own sprite and pool. This is also more efficient for pooling as the source never needs to be changed, as it is done in Squaby.
Would you require this functionality to change the source of sprites in a spritesheet at runtime?