It looks like you already know exactly what you want to check out by the developer ... why don't you just create his small website, which includes some of the ideas that you have already proposed. However, after 3 hours you are unlikely to get the full experience of any developer.
You can use something like a message precedence system, since it should be quite simple when any user can post messages that should be accepted by the administrator - and after they are accepted are displayed on the page.
This example may seem ultra-trivial, but much goes into something so simple: entering data into a database, creating a database, managing sessions, correct authentication and authorization, Ajax, if you want it, the correct separation of business logic from presentations, etc ..
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