Interesting. I believe that with Ranked-Choice Voting Williams would be the winner because only the top 2 with #1 ranking would be considered and then the #2 ranking from the 15% group would be split between them, giving Williams the win with 60% votes. With FPTP, Williams would also be the winner.

With approval voting, assuming they all pick only 2 (as picking 3 would mean everyone gets 100%, and this post already assumes some "perfect voting" anyway), Jones would also be the winner (just like in that post) with points from 100% of the voters. Williams would be voted by 60% of the voters and Smith would be voted by 40% of the voters.