i see your topic is interesting dude so i will answer it but based from what i know LOL
1.How did the Hebrews got their name? How did they become one of the protagonists in the Bible? What is their origin?
Me: Hebrew get heir name from Jacob, father of Hebrew. as far as i know they are the chosen one because of Abraham Grandfather of Jacob(in my language Yakub), thier origin..maybe more to middle east like mesopotamia.
2. How did the Christians got their name? their origin?
Christian is the one who believe in Jesus Christ, i don't know where christian got their name but maybe related to cruxified things about their origin.. they are from israel form Jesus himself to his Students, and then it spread through european and then through the world.
3. What are the different groups of people during the time of Jesus? their belief?
woow so many i think so far i know those are Pharisee and many other.their belief i think they are judaism but with their own way to think of god itself.
i hope it can give you some clue.