Interestingly, he and Caleb’s stats are pretty close, if not nearly identical, up to this point—even in rushing yards. I couldn’t help but notice that in the last game against Philly, it appeared Johnson leaned more toward a West Coast offense while still utilizing outside/inside zone blocking for the run game. Both Swift and Monangai eclipsed 100 rushing yards, which I suspect is because Johnson recognizes that Williams isn’t yet ready to make “splash” plays and wants to continue developing his learning curve.
Williams’ passing looked much as you described: primarily short passes, with the occasional longer attempt when available (like the TD to Kmet late in the game). What you observed with Nix is largely what I saw in Williams as well; the difference, in my opinion, is that Nix simply looked more polished executing it.