In dry conditions, Dudley, the Knifes Edge and Cathedrals are all within the abilities of most experienced hikers. Ranked by relative ease, its Dudley, Cathedrals and Knifes Edge. Keep in mind that Katahdin is a magnet that draws in hikers of different abilities from all over ,so the trail descriptions are oriented to a once a decade hiker and therefore tend to overstate the difficulty.
In windy conditions, Cathedrals have the least wind, Dudley somewhat more exposed and Knifes Edge very exposed. In wet conditions on the Knifes Edge do yourself a favor and go watch the moose at Sandy Stream pond
Dudley is basically a steep boulder hop, similiar to Caps ridge trail on Jefferson. No real exposure but a lot of climbing up and over boulders (leave your poles collapsed and in the pack going up). Cathedrals reminds me of Huntingtons Ravine trail, although Huntington's doesnt have anything to match the view from the top of each Cathedral. If you want to avoid exposure just skip the short spurs to each Cathedral. You get to use your hands in spots and there are some areas that have had slides in the past so if you are in group take care not to dislodge anything. Knifes Edge requires your hands and occasional foot placements. There are "chicken routes" in many spots that slightly cut down on exposure, but the reality is that in places the trail is 2 to 3 feet wide with a very steep drop on either side with no handrails. If you dont like heights and steep dropoffs, this isnt for you. On a windy day its not something to mess with.
Timing wise, on a good day, from Chimney pond the loop up Cathedrals, to the summit, then over Knifes edge and down Dudley is 5 to 6 hours. If you are doing it from Roaring Brook as a day hike add on a few more hours. If you are in good shape and camped out at Chimney the run up Hamlin in place of Cathedrals is a good subsitution and it gets you views into the adjacent basin. Doing this from Roaring Brook is possible but its a real long day and its easy to get dried out due to the long stretches of above treeline. The Saddle trail is strictly an escape route with nothing special except that its gets you down and into the trees as quick as possible. I havent done Helon Taylor to Pamola yet but it looks like a good but very exposed route as it gets you above treeline a lot quicker than going to Chimney pond.
I will note that going down Hamlin is a lot more impressive than going up it so you may want to do the loop clockwise.