The JSF problems I was having seemed to come out of nowhere. Ultimately, the .metadata log (thanks for the vector as to where to look for clues) was reporting that it could not find a Saxon8 JAR.
I ended up putting the Saxon8 JAR files in the (MacOSX) folder /Library/Java/Extensions and the situation is now completely back to normal.
For what it’s worth, along the way I discovered that JBoss DOES include a ‘JBOSS_ENDORSED’ reference into the Java classpath in the run.sh file for that application server. That helps JBoss but does not seem to do much for Eclipse when it comes to finding the Saxon8 JAR files.
Thank you very much for otherwise helping me make forward progress on this point.
Best Wishes,
Lance Drake