Conflicting libpng.16.16.dylib
I can think of some ways.


Backup your /opt/X11/lib/libpng.16.16.dylib. And replace the file with either symlink to the file under anaconda or directly paste the file. 
I think the environment variables can have multiple paths, like $PATH variable. I found that the path you have in front has the precedence over the ones that are written behind it. For example, if your path is /usr1/:/usr2/ then it should check the usr1 directory first and see if the required file exists, before moving to the second one. So you could possibly put your anaconda path in front of the /opt/X11/lib/libpng.16.16.dylib. 
I believe symlinking the file is the best way. I have experienced that kind of things before, I just had to add a symlink and it's fixed. 


This answer might explain your last question.