No, according to Jewish law, tribe is through the male, not the female. As such, when a couple get married, the bride joins her groom's tribe. Additionally, although the surname 'Cohen' used to indicate that a person belonged to the Cohenim, today, with intermarriage, it's possible for someone to have that surname and not even be Jewish.
In terms of becoming a Jew, there are two ways. The first is being the child of a Jewish woman. The second is to convert to Judaism according to Jewish law which can take anywhere from one to six years.
Please note that there's no such concept of "grafted" in Judaism, that is a Christian concept.
Yes. The name Cohen is Jewish to help prove it.
yes
The name "Cohen" (and variants) comes from a Hebrew word meaning "priest". By Jewish tradition, "Jewishness" is passed through the mother, not the father, so a Jewish man named Cohen who married a non-Jewish woman would have non-Jewish kids with the last name "Cohen". This isn't terribly common, as Jewish men have historically tended to marry predominantly Jewish women, but it's certainly possible for someone to have the last name Cohen and neither self-identify as "Jewish" nor be regarded by Jews (especially Orthodox Jews) as Jewish. It's also certainly possible for someone to be ethnically Jewish, but not adhere to Judaism as a religion.
no. he is jewish.
Yes, he is.
There are many famous people named Jack Cohen, and virtually all of them are Jewish.
Cohen, Schwartz, Freid
Cohen, Jovi and variants of these
From what I understand, Cano is the Spanish version of the name Cohen, which is Jewish.
Mayor Cohen supports same-sex marriage and is a member of Mayors for the Freedom to Marry.
Senator Cohen supports the legalization of same-sex marriage.
Ben Cohen is not Jewish. His great grandfather was Jewish and married outside of the religion. A Jew is one born of a Jewish mother. Ben was raised Christian. He has mentioned his uncirumcised status.