I'm not sure I like the transparency. But this does remind me of something similar with Beyond Earth.
This UI Tweak mod removed the citizen buttons completely, instead making the tiles themselves act as citizen buttons, and add a border to each tile to designate it's citizen management status like locked, working, border expansion, etc. You could still plop down the lock icon for locked citizens, say just above the yield icons. Make a green border around each worked tile.
This implementation will also completely eliminate the problem of the citizen buttons overlapping yields in strategic view, too.
Although I must mention that even at that time, quite a few users expressed their dislike regarding not seeing the citizen buttons. They found it an unnecessary barrier to have to remember what the border colors were supposed to mean.
I think a compromise can be reached with just using a green border to indicate "worked" status, and still use the padlock for locking, the 0/1/2 count for district slots, and the "in X turns" for border expansions.
I have no idea if this can actually be implemented in Civ VI, though...