I think it would depend on the day of the week. If you're talking about next year, which is on a Saturday, I would definitely attend that! Maybe not a brunch as most people sleep in that day. And you might get some people that have traditions that day that might not attend, but I don't know many people that do much on new year's day/night. Also, not sure if vendors might be more expensive given the holiday.
I would go if it were like a friday going into a saturday. But if it were during the week when I'm expected to work on the 2nd I probably wouldn't.
I know it is new year's day but honestly that rest after maybe partying the day before or drinking rather lol. I would go. That is not a day in which I would feel a wedding is inappropriate. I say do it. I cannot see any cons to it. Heck I have been to a wedding on Thanksgiving day ha ha.
I would attend. Fun story, my cousin was born on New Year's Day. So when he was younger and growing up, we'd do like a hangover party...the kids didn't get it, but the adults obviously did! It was a later in the day party and we had pizza, chicken wings, and ice cream cake. My family looked forward to it every year because it was such a fun chill way to start the new year. So I think you should go for it. People might not be fully into the drinking as they would during a New Year's Eve wedding, but like others said...if it's on a Friday or Saturday, who knows! People might welcome that!
I would attend a New Years Eve wedding, if it was on a Saturday or Sunday and worked with my schedule. I probably would not attend a New Years Day wedding, unless I did not have to work the following day.