Fine list General.
I would have to add Mats Wilander to that list. 3 titles at Roland Garros and I think 20 titles overall on clay.
I would also add Ken Rosewall. He had 2 French Open titles - 1 as an amateur, and 1 at the start of the open Era as a professional, but he also won the French Pro championship 4 times at Roland Garros as a professional when locked out of the amateur Slams.
Did you know that Rosewall, who turned 34 at the start of the Open Era in 1968, went on to win 44 singles titles from that point to the end of his career (inc. 2 titles in 1977 at the age of 43)? I believe he had a total of 35 singles titles on clay. 6 as an amateur, 15 as a professional, and 14 in the Open Era. Not bad for a guy 1.7 meters tall (5' 7") and only 67 kg (145 lb), who, according to Richard "Pancho" Gonzales, had a weak serve and a weak forehand. But he had probably one of the greatest backhands of all time. Rosewall was naturally left handed but played tennis right handed.
Respectfully,
masterclass