There is a way through code that you can load the assets from an external source as shown here Load 3D models at run time from a PlayCanvas application - #4 by yaustar
I’ve never tried from a JSON asset inside the PlayCanvas editor but it is possible for individual assets. Mappings to materials won’t work though from what I know.
Here’s an example using the raw JSON: How to create/load asset from Json variable (not from file or url)? - #3 by yaustar
Not that I’m aware. There may be a way to do it via the undocumented Editor API. @Leonidas Anything you have found that could help here?