Also, does Allah fall into the "jesus" category or is he his own entity? I'm not religious at all so someone explain this to me
Allah is the same God worshiped in Judaism and Christianity. The differences in the religions come in Jesus. Traditionally, jewish people believe Jesus was here but wasn't the son of God. Christians believe he was and Muslims believe he was a prophet, just like Muhammad. Jesus didn't even want to start a new religion in his name, he wanted to reestablish and renew Judaism, which was his religion. He wanted to change the way things had been done but it ended up sprouting another religion entirely because the Jews at the time disavowed him and thought he was a heretic.
So Allah wouldn't fall into the Jesus category but he would fall into the supreme being "God" category.
The reason for all the different Jesus' is, at least to me, related to the different depictions of him around the world. Every race has a different interpretation of him physically and even personality wise so every one of those interpretations has a seat at the table