What you have mentioned in regard to
slaughtering sacrifices at the shrines of Awliya’ is considered Shirk (associating others with Allah in His Divinity or worship). Anyone who does so is cursed. This is because they are offering sacrifices to other than Allah; it is authentically narrated that the Prophet (peace be upon him) said,
Allah has cursed the one who slaughters (sacrifices) to other than Allah
Therefore, it is impermissible to eat from the meat of the sheep and cows slaughtered by the graves of the Awliya’.
Reciting the Qur’an over the dead is Bid‘ah (an innovation in religion); it is authentically narrated that (Part No. 1; Page No. 198) the Prophet (peace be upon him) said,
Whoever introduces anything into this matter of ours (Islam) that is not part of it, shall have it rejected.
(Agreed upon its authenticity: Imams Al-Bukhari and Muslim).