Not sure of the specifics of the MP Star, assume there is some level of feedback to hit that triggers it. Hit X number of positive feedback with zero negative feedback. Might need to check with a mod or TimG.
The crown is for being a VIP member. For $20 or $25 a year you can support the site and have access to a lot of hidden features. The VIP lounge here, unlimited MP posts, Road Trip and quite a few more. Under your "User CP" is the Paid Subscriptions which explains it in detail.
https://www.dgcoursereview.com/forums/payments.php :thmbup: