问题1.play framework Activator: command not found

As stated in my comment, you'll want to add export PATH=$PATH:/full/path/to/activator/directory to your .bashrc file.

and 

activator clean compile 

from the play application folder worked for me.

then

activator run

However you also want to fix the version of scala-compiler use, and you want it to match your configured scalaVersion:

dependencyOverrides += "org.scala-lang" % "scala-compiler" % scalaVersion.value