Welcome flyinfiddlesticks. My thoughts are as follows.

1. If negatives are too dark or black, the picture was overexposed, or the film developed for too long/developer was too strong. Given this was a roll of film I ask was there any evidence of the frame numbers only the edge, or was this all black as well. If the frame numbers are there and the edge of the film is relatively clear then exposure is my guess as the issue behind the black frame. If all the film is black then your film has seen light between being in the cassette and being developed and fixed.

2. Once you have run your film through the fixer there is no second chance with doing what you tried. The fixer removes all of the unexposed silver that turns black during development. So you should not be surprised that a second 45min development made no improvement. Please note the developer does not 'lighten' a negative.

3. Developer turns the exposed silver black, the fixer removes any unexposed silver so that the negative does not turn black over time, then destroying your image/s.

4. My questions. Did you load the film spiral for the tank in total darkness? Is your tank light tight, does it have a lid? Your film was not exposed to a darkroom safelight at any stage before being developed and fixed was it?

5. I am not sure what your residue and odours were. I have not used Foma chemistry. I reuse my chemistry on many an occasion, unless I use 'One Shot/One Use' chemistry. The developing tank is used from start to finish of the developing and fixing cycle.