Would the Dwarfs be more willing to engage in those types of studies if they had a steady supply of Dawi-Zharr corpses, or does their cultural mores protect them as well?
No. The Dawi-Zharr are looked at as a source of shame for the Karaz Ankor, rather than existing completely outside of it, so desecration of their corpses would still be shameful. It would also be potentially problematic, considering the Dawi-Zharr have at least a few biological differences.
For that matter would they be willing to accept medical insights from humans and the Eonir haul? There are some biological differences but there are even more biological similarities, some of the knowledge should be cross-applicable. There's also that human biologist who conducted autopsies on Dwarven corpses and made notes on their biology until he was killed by Dwarves for desecrating Dwarven corpses. Would they be willing to use the knowledge gained from that to improve their medical practices or does it fall under the fruit of the poisoned tree? There's also that Skaven book on Dawn-Zharr anatomy we translated, would that be of any use to them or does that fall under the fruit of the poisoned tree doctrine again since its origin is both Dawi-Zharr and Skaven?
Dwarves aren't super big on changing their own methods and traditions based on input from others.