I think that’s a nice summary. Whether or not you can replace Pocket with DT is a question of personal preference; it would be easy enough to clip/save things to DT and mark them with a Tag “Later”, then collecting them in a Smart Group (or even several, based on additional criteria). That said, I like to use Drafts for things that are either active or haven’t got past the “important enough to go in DT”-barrier. It’s very much a question of your workflow and preferences.
Yes, I think you would do well to keep a reference manager - which one and to what extent you can get them to play together (saving you duplication), I cannot answer - various posts in this forum suggest that some level of intertwining will be possible.
Yes, you can (and I would encourage) use DTP instead of the folder structure on the Mac. I would caution against having a parallel universe here - neither will ever be up to date, with some things in one and some in the other universe. I urge you, however, to review any backup strategy you may have, or to develop one if you haven’t. I posted about mine here and have, in the meantime, added a monthly backup to WORM media.