Is it permissible for a man to shake hands with or be alone with his wife's sister, or her maternal aunt or paternal aunt, and is the temporary prohibition for these women the same as the prohibition for another man's wife?

It is not permissible for a man to shake hands with his wife's sister, or her paternal aunt, or her maternal aunt, nor to be in seclusion with them; because they are not mahram to him. Rather, they are temporarily forbidden to him. Permanent mahramiyyah is established by lineage, suckling, or marriage affinity. The wife's sister, her paternal aunt, and her maternal aunt are not mahram. Instead, it is forbidden to combine them with the wife in marriage, based on the Almighty's saying: "And that you take [in marriage] two sisters simultaneously," and the Prophet's (peace be upon him) prohibition of combining a woman with her paternal aunt or her maternal aunt. As for another man's wife, she is temporarily forbidden as long as she is under her husband's conjugal bond.