Praise be to Allaah.
There is nothing wrong with distributing sweets and gifts
at weddings and other happy occasions.
It is still customary in Muslim countries, and no one objects
to it. See the answer the question no.
With regard to cakes for the New Year, it is not permissible
to help with making them or selling them, because that is helping in sin and
transgression, because the New Year is not one of the Muslim festivals, so
it is not permissible to celebrate it or to help those who celebrate it.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
Congratulating the kuffaar on the occasion of Christmas or
any of their other religious festivals is haraam according to consensus,
because that involves approving of what they follow of symbols of kufr and
approving that for them, even if he does not approve of this kufr for
himself, as it is haraam for the Muslim to approve of the symbols of kufr or
to congratulate someone else for them. Similarly it is haraam for the
Muslims to imitate the kuffaar by holding celebrations on that occasion or
exchanging gifts or distributing sweets or plates of food, or taking time
off work and so on, because the Prophet (blessings and peace of Allah be
upon him) said: “Whoever imitates a people is one of them.” Narrated by Abu
Majmoo‘ Fataawa wa Rasaa’il Ibn ‘Uthaymeen,
And Allah knows best.