I think 4d is New Year because we enter into it after making New Year resolutions (remember those?) while we are often drunk. You're correct in finding a lot of the answers have a festive theme. eg.
45a Penny feels aggrieved at things such as gold. The answer, PRESENTS only makes sense in the fact that gold was one of the presents brought to the nativity.
I think you have the wrong letters in 9d, it should be N?N? T?E, which would give the very strange looking answer of NONE THE where ONE is for United in N{ew} THE (article). As in None the less, none the worse etc.
I have a couple of problems too:
19a Kid's application for awards in literature succeeded (4)
I have L?S? and it looks like LIST where S{ucceeded} is in LIT{erature} but how to parse the first part?
55d Goal not accounted for after clash to be reviewed (3)
I have A?M which means it has to be AIM (for goal) but what about the rest? All help gratefully received.