Both problems are probably because you are mixing two c++ libraries, libc++ and libstdc++. The official Panda SDK is compiled against MacOS SDK 10.6 and is using libstdc++ (7.9.0). If you compile a module or link with panda with code compiled against libc++ your program will crash almost immediately as one of the two libraries will not be initialised properly. SO you have to recompile your program using
--std=gnu++11 -mmacosx-version-min=10.6
And have a 10.6 SDK installed.
If you recompile Panda on your machine, you also need to recompile the third-party packages with the same SDK and c++ library, otherwise you just move the problem somewhere else (__ZNSsD1Ev is a string constructor and usually libc++ incompatibilities are popping up in string related code)