Replacing backgrounds in View/Try Mode

We're in the process of doing a rebranding of the products we have a bunch of view mode and try mode simulations built out for. We would like to replace all of the slide backgrounds with the rebranded backgrounds. All the dimensions, clicks, etc. remain exactly the same from the prior version to the new.

Does anyone know of a way to either replace the base layer background in an existing scene or an efficient way copy all the entities to a newly recorded scene (without having to manually copy-paste layers, timelines, and triggers separately)?