Jennifer,
I apologize for the delay in responding.
1. I'm not sure if this can be easily undone within portal or not other than by changing the form answers. I know that it could possibly be done through a support ticket, but am not sure otherwise.
2. Creating additional assignments - probably the best example would be a conference with multiple sessions. (e.g., a training day or perhaps a retreat with multiple breakout sessions) People would register for the main event, then choose which sub-events they will actually attend. For a ministry training day, that might indicate that they're coming to the November event, but attending the "Starting a Small Group Ministry" and "Practical Tips for Outreach" sessions.
3. Those later assignments are tied to the questions. You can have people pick a specific answer to one or more questions and those will have an Activity/RLC tied to them.
I hope that helps you a little bit.
For Him,
-Peter Schott