Praise be to Allaah.
There is no indication in either the Qur’aan or the Sunnah that would prescribe the actions described in the question. Based on this fact, these actions are bid‘ah (a reprehensible innovation) which is not permitted; we should avoid it and warn others not to do it. The Messenger of Allaah (Peace & Blessings of Allaah be upon Him) used to say in his khutbahs (sermons): "The truest of speech is the Book of Allaah, the best guidance is that of Muhammad and the worst of things are those which are newly invented. Every newly-invented thing is a bid‘ah, every bid‘ah is a going astray, and every going astray will end in the Fire of Hell." (Reported by al-Nisaa’i, may Allaah have mercy on him, in al-Sunan, Kitaab salaat al-‘eidayn, no. 1560).
It is permissible to pray for the deceased, without arranging a formal gathering, and without setting a specific date for doing so. We ask Allaah to help us and you to do that which He loves and which will please Him. Allaah knows best.