Some photo analysis for you. This image shows the bunker gas chambers from standing between the two disinfection barracks. As with your other photos, there is no chimney visible between the bunker and the canopy, at least not on the side that is unobscured, which is chamber A/III.

- bunker.jpg (82.01 KiB) Viewed 38 times
It's interesting to see the barbed wire fence here. This fence would not prevent anyone from seeing gas chamber operations. It would however work to prevent anyone from wandering too close to it during airing out.
At one point Höss sent out a memo warning everyone in camp Auschwitz to keep "at least 15 metres" from buildings being aired out.
https://www.historiography-project.com/ ... tz/201.php
This fence was not 15 meters from the bunker, but it did create a reasonable margin, especially if the back door was the side that was opened to air out.
This next photo may seem strange, but isn't this the back side of the canopy? The guard tower is in the correct spot.

- road construction 1.jpg (264.31 KiB) Viewed 38 times
Likewise for this photo. I will trust your judgement on whether it is Barrack 41 or not. I'm not sure anything useful can be gleaned from these photos. I just found it remarkable that a pre-liberation photo of the gas chambers was not noted as such.

- road construction 2.jpg (66.74 KiB) Viewed 38 times