So much fun stuff, where to begin.
Regarding this graph, I see that the CO2 levels and temperatures were similar to those today. The proto-mammalian therapsids were evolving just fine until the big disaster, then Lystrosaurus held out for a time, and the dinosaurs/lizards ruled for 150 million years. Perhaps there is an important difference in mammalian style vs lizard style metabolism that caused the failure of the therapsid line, leaving only a few tiny proto-mammalians to hide in the bushes for all those years. Should this worry us today with increasing CO2?
As to why the dinosaurs did not survive the meteor event(s) of 65mya, a theory I have not heard is that it/they probably destroyed the ozone layer for quite some time. I can see the poor dinosaurs dying of skin cancer. Note the creatures that did survive. Birds covered with feathers, frogs and salamanders living in water or under plants and rocks, alligators living and resting in mud bank caves, mammals covered with fur and living in bushes.
A great book is "When Life Nearly Died: The Greatest Mass Extinction of All Time," by Michael J. Benton, 2003. There is an interesting graph on pg. 172 showing "radiometric ages, the carbon isotope curve, and the ranges of 333 species of fossils identified from 90 metres of rock in the Meishan quarries. A, B and C mark the three apparent pulses of extinction." These three pulses occurred over a million year spread, and could coincide with several boloid events.
For those who like the vulcanism explanation, see pg. 275 with "A summary diagram showing how the eruption of the Siberian Traps led to major atmospheric changes and to the collapse of most of life on Earth 251mya." [I would post these, but don't have the computer capability or knowledge.]
Regarding the idea of contrecoup damage, is this the same concept as when a bullet hits a skull it causes a small hole going in but a big hole or bulge on the opposite side of the head? If so, then this was my initial thought for the Yucatan/Deccan Traps situation, until I heard about the "Shiva Crater". There is a lot on google there. At the end Permian, all the land masses were pretty much stuck together as Pangea. I think that the Bedout and Antarctic Craters would have been toward the south end, and the Siberian Traps toward the north end, but I am not sure there would have been enough oppositeness for a ballistic type effect. That is why I think there may be a crater hidden under the Traps.