My 2 cents...
First of all, both the turkey and the muffins sound incredible, and I may have to have a fake Thanksgiving next weekend just as an excuse to make them. Also Tipsy Sweet Potatoes. Between checking the champagne and the whiskey for poison, though, I may need a cook's helper!
I don't think there's a divide in the comments here: Everyone agrees that the OP has the right to set her own menu (which sounds delicious, btw), the right to make new traditions, and should not have to expend the time, effort, and money into making dishes she doesn't enjoy.
What some of us, myself included, feel is that while OP also has the right to ask her guests not to bring any additional food, it's not particularly gracious nor inclusive on Thanksgiving to refuse to allow her guests to bring food to add to the menu. This isn't a dinner OP is hosting for friends, in which case I would be put off by a guest showing up with an addition to the menu. It's a holiday in which sharing dishes is common, where there are traditional foods that people look forward to, and it's a holiday whose entire point is about being thankful for what we have - it just seems a bit against the spirit of things to refuse to allow mashed potatoes and whatnot to be on the same table as what the OP made.
And from the OP's update it sounds like she's happy to bend a little to make sure her guests have a great dinner, so all seems well.