Praise be to Allah.
Ibn Al-Qayyim (may Allah have mercy on him) said:
“It is not permissible for the Muslims to attend the festivals of the polytheists , according to the consensus of the scholars whose words carry weight. The jurists who follow the four schools of Fiqh have stated this clearly in their books… Al-Bayhaqi (may Allah have mercy on him) narrated with an authentic Isnad (chain of narrators) from `Umar ibn Al-Khattab (may Allah be pleased with him) that he said: “Do not enter upon the polytheists in their churches on the day of their festival , for divine wrath is descending upon them.” And `Umar (may Allah be pleased with him) also said: “Avoid the enemies of Allah on their festivals.” Al-Bayhaqi (may Allah have mercy on him) narrated with a good Isnad from `Abdullah ibn `Amr (may Allah be pleased with him) that he said: “Whoever settles in the land of the non-Arabs and celebrates their new year and festival and imitates them until he dies in that state, will be gathered with them on the Day of Resurrection.” (Ahkam Ahl Adh-Dhimmah, 1/723-724)
With regard to congratulating them on their festivals, this has already been answered in Question no. 947 , which we advise you to refer to.
And Allah knows best.