They are not entitled to inherit from him.
This specific text was not part of a reported supplication from one of the infallibles but it is permissible to read it for seeking intercession and entreat Imam Ali bin Abi talib by his rank to almighty Allah to fulfill the needs since all matters are in His power plus he made the prophet and his household (peace be upon them) intercessors.
We are not aware of a narration that addresses this issue.
It is allowed to use the rennet that is extracted from the animal that was not slaughtered according to Islamic laws since it is Tahir and exempted from the prohibition of using parts of the dead animal.
We are not certain of the sequence of the versesâ€™ revelations. We are sure of the fact that the Quran is the current contemporary one.