Can a Kohen who marries a gerusha give eidus, and does a Mashgiach have a status of an eid?
kol tov
Answer:
A kohein marrying a divorcee violates a Biblical prohibition, ans as such is disqualified from legal testimony [eidus].
A mashgiach is not giving eidus per say, yet he certainly has to be an observant Jew and known to be trustworthy and reliable, as well as being careful himself in the laws of kashrut.
