Question

Currently working on a 50-track song with many groups of tracks so unhiding is quite a task.

Answer 1

I figured it out in case you haven't! In the mixer, click on the three bars in the bottom left hand corner (above the midi icon). A window opens listing the channels (number - dot- icon - name.)  Click on the channel's name you want to unhide/show while holding down control or shift depending on what you're selecting. Make sure you are clicking on the channel's name, it doesn't work elsewhere. Hold down Ctrl+Alt and click on the dot.