squidcharger please share Language & Region
system preference screenshot, I guess that can also make some difference in some cases.
Also, can you please summerize all the issues again, as I guess there's some confusion, because your initial post says, WebKit crashes when you CMD+Click the link, but your earlier logging shows thats while ProcessSwapping which is only possible if you navigate to current webpage, not the new tab.
So, most probably there's two different issues, so please try your CMD+Click issue on the Dev build I have sent, and if that's fixed, we can look for second issue (Process Swapping on Cross-Site Navigation), and looks like new process is getting failed to launch.
Try using below file (last time I guess I sent wrong version)