Is it possible to change the speed of scrolling text? No not really, you can have some influence on the speed by changing the length of the title. But thatis often not what you want. There are (YouTube) examples to show you what can be done and how.

When using multiple lines of text with effects can I arange the order of what line starts first. I thinkthat the trick is to addmuplie titles into the timeline and assign the required effects to each. By ordering the lines in the time line, you can also define the order of appearance

Can have each line have a different effect? if you take the above approach: yes. Also when you add more titles to the same title block it is possible to give each title (line if you want) different settings.

Part of the fun of editing is to try (new) ways and to get to new a creative solutions that will astonish your viewers. My suggestion: Try to experiement with the above in PD and discover the unexpected. Maybe your conclusion is that my answers are wrong;
Let me know. Have fun!