It seems you are more familiar with the Qt platform than any of us I suggest we start focusing on the GTK theme, and once we are advanced enough to not have duplicating the work or late changes again, we reach out the Kantum’s author to get some help on configuring a similar look than our current theme advancement. Would you like bridging that gap on the Qt side for us?
@wfpaisa: I’ve added you to the team, great work on those teams! Do not hesitate to help where you can
There is plan for the snap team to reuse the installed system theme, as well as icons and others, so it shouldn’t collide on the long term. At worst, we do include them in the platform snap, as we do nowdays.
I started to create a FAQ btw, seeing some similar questions (and misconceptions from the press in particular) being spreaded: FAQ: Ubuntu new theme