Clayne:
The black trousers (frame 20a are darker than 21a) should plot in the toe of the curve, that is at the point where density starts to build. What I see is those black trousers at around 0.70 (guesstimate) which is on the linear part of the curve normally white skin tone would plot there.
Shadow information must not be on the linear part of the film curve to maintain good balanced negative ideal for reproduction.
I don't know what 'hot development' means-do you mean over development? Sure I see that as well as over agitation– those are not the reason for the 'crushed' lack of detail in the whites and lowering of definition of the grain.
Given that I trust that time and temp were ballpark for this film developer combination, and that the shadows on the underexposed area (in the bar shot) remain low in density but high in contrast development isn't the major factor, agitation can at maximum give a density of x2 (between no agitation and continuous)
Any variation in exposure will increase the appearance of grain. Overexposure increases grain especially in the area of mid-upper highlight.
The grain changes character as well depending on a host of factors, mainly as light scatter starts to be a factor within the emulsion softening the appearance. In our tests we found this 'grain blunting' normally occurs at around 3-4 stops overexposure.
Underexposure and correcting in printing give 'pepper grain' especially in the lower mid tones which is different to the appearance of grain in overexposed regions.
(you can see this in the thin and thick negs posted)
There is certainly a problem with these negatives; they are far from normal– the randomness of density in the frames points to overexposure with some frames and with normal under exposures on some; the contrast over the whole film showing slight over development/agitation.
They may be recoverable, and yes I've been able to recover both in the lab and under test environment of up to nearly 8 stops-but those are far from optimal.
My prognosis is mainly exposure, 30% overdevelopment and over agitation.
The neg on the left is how you see it posted by the OP above. On the right I've attempted to mimic a neg that looks normal-slightly over.
That is a difference of about 4-5 stops in density to make the left exposure look like the one on the right.