1) Titles: Just add Text. And yes, you will need to check datasheets for many components. If you are not sure, you can always check how we do it in our open source projects: http://www.imx6rex.com/
2) Block diagram: The main point is, that you understand how difficult it is to understand a schematic without block diagram. And as I can see, you already understand that

3) Port: This may help you: How to add a Page number to a Port in Altium Designer
4) Net name: Use what you think is clear name
5) Hmm, I am not sure why

- Robert
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