You've made a persuasive case to justify the conclusion that Shelley and Lovelady's time estimates can not be trusted or relied upon.
As for the sequence of events, I still don't understand how Shelley and Lovelady could have arrived at the stairs before Truly and Baker. In the 1978 made for TV movie "Ruby and Oswald" there is a clip showing actors playing Truly and Baker running from the front entrance counter to the elevators and they needed no more that 20 seconds to get to the stairs. So, if Shelley and Lovelady were still on the front steps when Truly and Baker went inside the building, how could it be that Adams saw Shelley and Lovelady but not Truly and Baker?
On the other hand, Shelley and Lovelady would have been able to enter the first floor at the side door within seconds after Baker and Truly entered the building. If that's what happened, it explains how Shelley could have seen Eddie Piper, who placed himself right in their line of sight in his testimony. Adams also had a clear line of sight to where Shelley and Lovelady said they entered. I still believe that she could have seen the men just a split second before leaving the building, just before Truly and Baker got there.
I have definitely been emphasising the veracity of what Adams testified to in her WC testimony as she reiterates the same points in the "Lost Interview". I think this is further supported by her statement to the DPD where she first mentions seeing Shelley and Lovelady.
She constantly asserts that she leaves the fourth floor within seconds of the last shot. She states it was immediately after the last shot and that she had made the decision to go and investigate before the limo had even reached the underpass.
Seconds later Dillard takes a pic which includes the fourth floor window Adams was watching events out of. She and Styles are nowhere to be seen. This is to be expected if she has already decided to get downstairs.
I have demonstrated that Adams could've been on the first floor 35 -40 seconds after the last shot and before Truly and Baker make it to the area near the elevator The Stroud document confirms that this was indeed the case.
Adams sees Shelley and Lovelady as she runs from the first floor stairs to the back door. She is certain and precise about their position:
Mr. Belin: When you got to the bottom of the first floor, did you see anyone there as you entered the first floor from the stairway?
Miss ADAMS. Yes, sir.
Mr. Belin: Who did you see?
Miss ADAMS. Mr. Bill Shelley and Billy Lovelady.
Mr. Belin: Where did you see them on the first floor?
Miss ADAMS. Well, this is the stairs, and this is the Houston Street dock that I went out. They were approximately in this position here, so I don't know how you would describe that.
Mr. BELIN. You are looking now at a first floor plan or diagram of the Texas School Book Depository, and you have pointed to a position where you encountered Bill Lovelady and Mr. Bill Shelley?
Miss ADAMS. That's correct.
Mr. Belin: It would be slightly east of the front of the east elevator, and probably as far south as the length of the elevator, is that correct?
Miss ADAMS. Yes, sir.Slightly east of the east elevator and as far south as the length of the elevator.
In the diagram below the circle marks this approximate area and the line shows Adams' approximate route.

Adams can be sure of this position because she has an interaction with them:
Mr. BELIN: Now what did you do after you encountered Mr. Shelley and Mr. Lovelady?
Miss ADAMS: I said I believed the President was shot.
Mr. Belin: Do you remember what they said?
Miss ADAMS. Nothing.
Mr. Belin: Then what did you do?
Miss ADAMS: I proceeded out to the Houston Street dock.In my opinion, it is impossible for Shelley and Lovelady to get down to the west door and into the position Adams sees them within 35 - 40 seconds.
Another problem with the west door theory is that Adams is racing towards the Houston Street loading dock door and would have her back to the west door. She would be running away from it and she would not have been able to have any kind of interaction with Shelley and Lovelady.
On top of that, the west door theory is relying on the word of Shelley and Lovelady, two liars who are specifically lying about their movements after the assassination.
So, how do Shelley and Lovelady end up near the elevators before Truly and Baker in the theory that emanates from taking Vicki at her word?
In Reply#403 I brought together as much relevant evidence as I could to recreate the seconds immediately after the assassination regarding the movements of Shelley and Lovelady. It culminated in this series of identifications:

According to the theory I'm developing here, the above pic shows Baker almost at the bottom of the steps, near where Shelley is standing. Lovelady is a few steps up listening to Gloria. But note Truly, he is the furthest away from the front door and is looking the wrong way.
As the seconds roll on from this point, Baker makes his way up the steps (probably the east side of the steps as he is remembered by Pauline Saunders who is stood on the east side). Baker enters the lobby and wants to find out about getting up through the building. As Baker is moving up the steps into the lobby, Shelley and Lovelady make their way up the steps, pass Baker in the lobby and move into the first floor working area. They are followed up the steps by Truly who enters the lobby and goes straight to Baker. He and Baker have some kind of interaction before they head off for the elevators.
Shelley and Lovelady are just a few seconds ahead of them, they arrive at the position shown on the map above where they are seen by Adams. Adams exits through the back door and Baker and Truly arrive where Baker notices two white men just stood around the area near the elevators.
Baker makes this point in his WC testimony - as he enters the building he is aware of other people entering with him.
Mr. Belin: What did you see and what did you do as you ran into the building?
Mr. Baker: As I entered this building, there was, it seems to me like there was outside doors and then there is a little lobby.
Mr. Belin: All right.
Mr. Baker: And then there are some inner doors and another door you have to go through, a swinging door type.
As I entered this lobby there were people going in as I entered. And I asked, I just spoke out and asked where the stairs or elevator was, and this man, Mr. Truly, spoke up and says, it seems to me like he says, "I am a building manager. Follow me, officer, and I will show you." So we immediately went out through the second set of doors, and we ran into the swinging door.It is not beyond the realms of possibility that these people entering at the same time as him are Shelley and Lovelady who are closer to the front door than Truly is. It should be noted that, according to Baker, Truly arrives on the scene
after the people who have entered with him.
The reason why I think Shelley and Lovelady are being truthful about where the re-entered the building is a video clip that Gerda Dunckel made some years ago, which shows Shelley and Lovelady walking in front of the TSBD towards the parking lot.
I had hoped to find it in the photo galary but it isn't there and I haven't found it elsewhere either. There is however another clip (# 10 in Gerda's collection) which (I believe, but do not know for sure) shows Shelley talking to a police officer in the parking lot. If it is Shelley, I also can't tell when the footage was shot. I would love to find the other video though. Perhaps another member has it and can post it.
I know the Dunkel clip you're talking about but the truth is that a close analysis of this clip shows that these men are not walking together. At the beginning of the clip one man is behind the other and as it rolls the man at the back moves quickly past the other and keeps going. Neither man looks back towards the steps where they are supposed to see Baker at the bottom of the steps. Neither man has run to the concrete spur, as both men lied, I mean, testified to. I think it was Alan Ford who had the rare insight that Danny Arce was a good candidate for the slower of the two.
I certainly don't buy it's them and have put a case forward for Shelley and Lovelady still being at the steps when Baker arrives, a position they can realistically make it to the back of the first floor while Truly talks with Baker.
Final note - there is definitely something going on with the west door. They are mentioning it for a specific reason. It is doubtless something to do with whatever it is they are trying to cover up.