When we were there last December, we went to
MVMCP on a Tuesday night Dec 10. They had the regular fireworks at park closing 6:00pm and then the special MVMCP fireworks at 9:15 I believe. They had fireworks at MK everynight at regular park closing in December last year, see the hours link above. Since it gets dark early, they don't have to stay open late to have them. Of course, they have cutback this year, so that doesn't mean it will happen this year.