Trying to sync up Adams', Stiles', and Garner's trip down the stair with when Oswald was on the stairs is an exercise in folly. Nobody was running a stopwatch on the day of the assassination, so everyone is guessing about when they were on the stairs. They could have been on the stairs before or more likely s little after Oswald. Since they were all going in the same direction, there is no reason to believe they would have crossed paths.
You were non-specific about what Dougherty's observations regarding Oswald you were referring to. If you are referring to the fact he didn't notice Oswald brought a package into the TSBD, this doesn't mean he was confused or cognitively disabled. It means he was human. People just don't take note of mundane details that wouldn't have seemed the least bit important at the time. Our brains do not have DVDs imbedded in them. We only remember fractions of the things we see, and when asked about details later on, our brains try to fill in the blanks, usually somewhat inaccurately.
Ok , Dougherty places himself on the 5th floor and briefly on the 6th floor at the time that Oswald was on the 5th floor and shouted for the elevator at 11:45. Dougherty never left the 5th floor except to briefly go up to the 6th floor then returning 5th floor again. He is on 5th floor from 11:45 till 12:30 basically. He supposedly then took the east freight elevator down to the 1st floor to meet Eddie Piper at 12:31 approx.
So during this 11:45-12:30 period of time that Dougherty was on 5th floor the sequence of other persons moving about occurred:
11:45 All other employees on 6th and 5th floor , except Oswald and Dougherty , leave and take the 2 freight elevators down to the 1st floor.
11:45 Oswald on the 5th floor or 6th floor , shouts to send an elevator back up to 5th floor (or 6th floor?)
11:45-11:54 Oswald is not seen by anyone including Jack Dougherty who is still on the 5th floor.
11:55 Givens ( presumably ) takes an elevator to the 6 th floor and sees Oswald on 6th floor. There is no conversation between them, even though Oswald probably saw Givens get off the elevator to go find his cigarettes. Oswald did not request that Givens send an elevator back up, nor did Oswald ride back down with Givens even though Oswald had shouted to send an elevator back up at 11:45.
12:00 Oswald is seen on the 1st floor by Eddie Piper. Jack Dougherty is still on the 5th floor presumably but has no verification of being seen by anyone there from 12:00 until 12:37 approx when Baker/Truly come down from the roof using an elevator to go down to the 4th floor where they met Sawyers team.
12:05-12:23 Bonnie Ray Williams was on the 6th floor. He used one of the elevators get there. Dougherty was still on the 5th floor at this time according to Dougherty. BRW did not see Dougherty or Oswald during this period of time nor did Dougherty see or hear BRW elevator passing by the 5th floor.
12:01-12:14 Oswald is not seen by anyone ( or they did not remember seeing him)
12:00-12:10 Mrs Reid , Carolyn Arnold, Virgie Racheley and other female employees are eating lunch in the 2nd floor lunchroom. None recall seeing Oswald then.
12:10-12:15 Mrs Reid and the female employees exit the lunchroom , trek 100 ft of hallway to the front staircase, go down to front lobby and go stand outside of the front entrance on the steps or further out on the sidewalk nearer to elm st. None see Oswald.
12:15 Digital clock time of TSBD roof clock: Arnold Rowland sees a light completed man that he described as “Latin” at the 6th floor SW window holding a rifle which Rowland could see had a scope on it. He saw that detail from 255 ft away approx. At the same time , Rowland noticed a black man “ hanging out” the other SE corner 6th floor window, and estimated the lower half of window was all the way up. ( ie: higher than the 15.5 inch height it was at time captured in Hughes film. Presuming the “ Latin” man was Oswald , then Oswald was on the 6th floor at SW window at 12:15.
If Oswald is the 6th fllor shooter then the following sequence begins:
12:01-12:14 Oswald was not seen This would be the period of time perhaps he could have assembled the rifle and then be seen by Rowland Arnold at 12:15. Where Oswald would least likely be seen assembling the rifle is in a storage office on the 7th floor.
12:15:30 sec, Oswald retreated from SW window , placed his rifle back in the paper bag( otherwise why would the bag ever wind up being at the SE window?) , hid the bag probably between boxes along the east aisle of the 6th floor as he made his way to the rear staircase.
12:15:30-12:16:45 Oswald descends staircase at normal pace reaching 2nd floor lunchroom and sitting down.
12:17 Carolyn Arnold has returned to the 2nd floor lunchroom to get some water ,
having left her friend Virgie Racheley at 12:16 ( possibly when they both were going down the front staircase to the 1st floor lobby ) Arnold sees Oswald sitting in a booth (or chair?)
12:18 Carolyn Arnold has left the lunchroom and probably made it down to the front lobby and then went outside to stand out if from of the TSBD.
This is a complicated sequence to work out with BRW on the 6th floor from
12:05 to 12:23, Jarman amd Norman taking elevator from 1st floor to 5th floor at 12:23 and Jack Dougherty on 5th floor and briefly 6th floor between 12:45 and 12:30.
Somehow nobody saw or heard Oswald going up or down on the stairs , or going up to 6th floor after he was seen by Piper. No one saw or heard Oswald moving 3 boxes just about 1 minute after BRW left the 6th floor at 12:23 , taking an elevator from 6th to 5th floor and joining Norman and Jarman who had arrived to their windows by 12:23.
And the anomaly is even more difficult to resolve with Jack Dougherty on the 5th and 6th floor who saw nor heard anyone between 11:45 and 12:31 and no one saw Dougherty from 12:00-12:37.
I can see why the WC did not wish to get into this thicket of uncertainty , but I’m going to keep trying to figure it out cause it’s an interesting problem.