As for workflow, I would bypass GoPro Studio and injest footage directly into your editing app of choice. All of them support multiple plugins for fixing fisheye, not to mention numerous other effects.
I'd do the rough cut right away. Then stabalize (just the clips that made it into the rough cut). Consider saving out (exporting/rendering) the stabilized clips, then reimporting them. It uses up disk space, but allows you to work going forward from a base set of stablized clips.
Refine the edit.
Color correct (optionally export clips for correction in another program, i.e. Resolve)
Color Grade, apply effects, add titles.
Export a full resolution "Master" copy to your local disk for safe keeping.
Export to: Vimeo/YouTube, local disk, etc.
Go back into project and clean it up. Do it right away before you lose your intimate familiarity with the project. Delete render files and even transcoded edit files. Just keep the original footage. You can regenerate everything else any time in the future by opening the project and rendering.