Of the courses I've played:
Shinnecock: 6
Oakmont: n/a but 10 if I really had to pick one
Pebble: 16
Merion: n/a but 14 if I had to pick one
Sand Hills: 9
Winner: Sand Hills 9
Sorry, but I disagree with all your selections.
A course is a sum of its parts.
#6 at Shinnecock is the 1 handicap hole.
It follows a short par 5 which almost always plays downwind, precedes a par 3 which preceeds a short par 4.
It is very appropriately positioned on the course and adds to the magnificent flow of this golf course.
It is a great strategic hole with multiple options and routes of play:
a. 6 is usually played in a cross, head wind which hurts yardage off the tee. If you take the left corridor (safer) this leaves a longer and more accentuated diagonal approach over the front bunker from over 200 yds.
b. If you take the more aggressive approach up the right side (which has been expanded a bit in recent years) it opens up to a more receptive approach. Wind is cross from the left which increases your chances of ending up in the right rough with less of a chance of reaching the green and the real possibility of ending up wet.
c. An overcooked bomb off the tee up the left side could end up in one of the bunkers on the left "corner" and leave you in the uneviable position of a negotiating first clearing the water hazard. Or sensibly laying up to the right...but not too far.
d. For shorter hitters it is a simple exercise in not being greedy and laying up your second well short of the water on the aforementioned better angle for the approach and trying for par that way.
e. Piggyness on the part of the short hitter or the less skilled in attempting to go left of the water to get closer to the green will leave a difficult pitch for even the Mickelsons of the world to a fall away part of the green with the high end of Flynn's "potato chip" just over the bunker.