Rabbis.
Judaism was in what is now called Israel. Its holy book is the Tanakh, which contains the Torah and the prophetic books.
The holy book of Christianity is the Bible. It has two main divisions - the Old Testament and the New Testament. The Old Testament is basically the same as the Tanakh the religious book of Judaism
The Torah
A Rabbi or a Cantor (or anyone for that matter) can interpret and teach the laws of Judaism.
Halakhah (הלכה) which means "the way"
Yes there are still religious groups called the Rightouse like Christianity and Judaism, or Islam.
The Tanakh (Hebrew Bible).
Sounds like a Zen koan. In Judaism, a Jew is fully a member of the Jewish people if he/she was born Jewish, or had a valid conversion into Judaism. Religious Judaism holds that a Jew can most fully express and nurture their Judaism by living according to the Torah. This is called by several names: religious Judaism; Torah-Judaism; Orthodox Judaism.
No. The Religious Text of Judaism is the Jewish Bible or Tanakh. The Zend Avesta is the Holy Book of Zoroastrianism.
A practitioner of Judaism is called a Jew. A Jewish religious authority is called a rabbi.
Jewish law is called 'halacha'.