Drush alias files aren't being found
I have my drush alias files at
  ~/.drush/[hostname].aliases.drushrpc.php
  […]
  But my other [hostname].aliases.drushrpc.php files cannot be found in
  drush status


The filename should be  ~/.drush/[hostname].aliases.drushrc.php. not [hostname].aliases.drushrpc.php: Your filename contains an extra p. See example.aliases.drushrc.php.