ProRes 422. That is more than enough for 4K GoPro Protune footage. And I mean just 422, not 422 (HQ) which gains you nothing in image quality when starting with GoPro footage. Also note that in that workflow, I hold off transcoding to 422 until I have to. Ultimately, I only transcode the portions of the clips that are used in the timeline. I do this to save time and disk space, and because Final Cut (unlike Resolve) can edit GoPros 4K h.264 files just fine. I can even edit h.264 at 4K on 2013 MacBook if I want to.
Mostly use Final Cuts stabilizer. Also use warp stabilizer in after effects. Looking into
www.reelsteady.com
I'm hear Resolve's new non linear editor is everything from OK to very good. Haven't really used it beyond loading clips to use on the color tab. If your on a Mac, isn't iMovie free? It has a stabilizer - and you'd be learning a similar user interface.
Don't get Neat Video or any noise removal software at all. Just shoot in good light and you won't have noise anyway.
If noise removal is a must, then note that the full version of Resolve has good noise removal tools. What would that cost you versus getting Neat?
And let's not forget iMovie - even if it's not free it will be cheap.
A quick note: If your getting back into the game after some years, its an Adobe world now. The jump from Final Cut 7 to X was a disaster and Adobe Premiere has taken over, along with their other software like after effects.
If your asking why I use Final Cut, it's just personal comfort level. If your asking about the workflow, it's a pretty standard workflow. It does help save disk space since you only transcode the portions of clips you use to 422.
That's probably one big disadvantage to using Resolve 12 on your MacBook. Resolve's performance editing h.264 is poor. That forces you to transcode to 422, and that means massive file sizes.
I think downscaling to 1080P is smart and your not missing much. First of all, things are progressing fast, but for now I think 1080P is more than enough for the web. Second, when you shoot in 4K or 2.7K, and downscale to 1080P, you get a sharper picture with better color and detail than if you shoot at 1080p to start. Also, downscaling reduces noise a bit if there is any.