Well for the first question, all three listed religions are “Abrahamic Religions” or the stem from the same source (if Abraham truly existed). Biblical standings say that Abraham was a Hebrew (so a form of Judaism existed with him), Abraham’s son Ishmael begot Islam, and from Isaac you got the lineage of David who begot Jesus.
Belief or practice wise, all three religions would believe in the existence of a Christ or savior (although Jesus as that Christ varies. All three are monotheistic, or believe in one God (YAHWAH, ALLAH, or Christ; all three believe in a Sabbath day (either Sunday or Saturday) as a day of rest from societal labor; all attend places of worship (mosque, temple, or church); all three have religious leaders (priest/minister, imam, or rabbi); all three have holy books which tend to coincide: Judaism (the torah and wisdom books), Christianity (the torah, wisdom, and gospel books or the bible), Muslims (the Torah, Wisdom, Gospels, and the Quran).
You can research many more specifics, in truth all three religions share 90% or more of their beliefs, what varies are practices and appearance, which are primarily guided by politics and economics.