Hi George,
Since this is a "non-profit" enterprise, should I use the .org or .com domain tag?
This is really up to you, many non-profits use .org domains, but there are no rules governing who can or cannot use .com or .org. You could even register both extensions for the same domain name, if you wish, so that people can find you more easily.
Also, I was testing ideas with: georgekbrannenfund /Wordpress.com, and was indecisive about "bundling" or not; as usual I went to find more data; now, I retry the same domain name and I'm told that domain is already "in use" and is not available.
You have purchased the Pro Bundle and registered the domain name georgekbrannenfund.com on January 5, 2013. You can review (and cancel, where applicable) your upgrades under Store > My Upgrades in your Dashboard.