Hi there, @samraul. Thanks for your concern; let me address your points below:
The star symbol is required and can be available through 02 main strategies: Hardcoded value in all Stars created by your Smart Contract or receiving it as a variable in the Constructor.
You are correct; you need to check against one created in previous steps. The students are free to create a new one if they wish to.
They are properties available in all Stars created in your Smart Contract.
As I disclaimed in point 1 above, it is not mandatory to be in the Constructor.
Finally, here is the highlight from the project's rubric disclaiming the usage of the Star symbol:
https://github.com/udacity/nd1309-p2-Decentralized-Star-Notary-Service-Starter-Code/blob/ad8d65e2b0fb69737c481570eeb85953f2599936/test/TestStarNotary.js#L78-L81
This test seems to be mixing the concepts of star information vs contract information.
star symbol
Thanks.