Present the features well, in good looking scenes
Polish the user experience to the bone!
Should I get a separate email for the add-on since the license statement appears to require that I provide a way to contact me.
Yup
Should I start a separate website or make a page on a current website for the add-on?
Completely overkill 
Licensing? I’m leaning toward the GNU General Public License, since that’s what Blender itself is released under. Pros and cons?
You have no choice unfortunately/fortunately depending on some’s point of view
Since I’ve been broke most of my life and have relied on free add-ons, and have paid for add-ons whenever I felt like I could, I am considering releasing it as free but encouraging donations. What are the pros and cons of that?
If you believe you have a good plugin with a bright future, that users can rely on every day and in the long term, then a good monetization solution is needed.
encouraging donations.
Generally, donation rates are extremely low
What are the best platforms to release it on?
I would also like to release it for free at first to get feedback about the add-on. Is that a good idea? Is there a best way to get feedback on an add-on in a kind of pre-release?
WIP topic works great for this purpose; i started like this with my topic
Geo-Scatter - 5.4 Scatter Groups 