Definitely a fun read. Debugging crashes has, in the last decade or so, become something a bit like a "lost art". Noone looks at coredumps in the cloud ...
I don't want to outdo you on Solaris debugging (plenty of old-time Solaris folks at Oxide who are totally capable to show how to get things like open files and their contents from a coredump, or how to configure the system to include those should it not be there ... etc ... etc ... Solaris has the best coredumps for all that's worth ...).
A note on the fix side of things though, while adding pthread_get_attr_np() for stack location/size gives Solaris the Linux interface, it already has its own for those - pthread_attr_getstack{size,addt}(), see https://docs.oracle.com/cd/E19455-01/806-5257/6je9h032l/inde... - I happen to remember this because I used this decades ago somewhere in the Solaris name lookup code to choose at runtime between using alloca() and malloc() ... don't ask. Those were different times.