My 2cents - I wish I'd thought of the cli lines at the end of my script when I did something similar! :D
I also had a similar script to set up the code base, so it would clone Moodle and set the appropriate branch, then would do the same git clone for each plugin, and where appropriate would cd into the plugin folder and set the relevant branch. Not much use for a single site as I had to maintain the script with all the plugins and relevant branches (where it didn't just use master), but if you want to spin off quick identical test/WiP dev sites, it was quite handy.
I also had a similar script to set up the code base, so it would clone Moodle and set the appropriate branch, then would do the same git clone for each plugin, and where appropriate would cd into the plugin folder and set the relevant branch. Not much use for a single site as I had to maintain the script with all the plugins and relevant branches (where it didn't just use master), but if you want to spin off quick identical test/WiP dev sites, it was quite handy.