Quick addendum here:
Ford addressed this issue in the 33.5 kWh packs by adding clamps to keep the cell stacks compressed. At first glance, this seems like something that it would to be easy to retrofit the 23 kWh packs with. However while there is plenty of research on compressing new pouch cells, I could not find any on compressing aged pouch cells.
My concern is that the pressure would crush the hollow heat exchanger plates and we'd be right back at square 1. The ideal solution would be to vent the accumulated gas somehow. While doing so safely is relatively straightforward, there doesn't seem to be a reliable way to re-seal the cells afterward, as the electrolyte contains a solvent which would degrade any adhesive patch. Since the electrolyte and the gasses that cause the cells to swell are both highly flammable, this makes such a solution a complete non-starter.
Unless I can find a way of reliably re-sealing the cells, I'll probably just try the clamp retrofit without venting the cells first. Maybe with a quick shutoff valve installed in the coolant loop