Client-Server architecture: 100% Android (Android as a server) or J2EE+Android?

Context

I am considering going into a client-server architecture with Java. The idea is that several Android tablets (let's say around 15) need to display a content from a server. Content can vary times to times (e.g. day display v/s night display). Furthermore, tablets will also display a Yes / No ( or a Green / Red ) button plus a free-text comment field.

Comments are gathered and sent daily as a reporting via email.

So there is a double-way communication:

• Server send to clients content to display, content may be updated
• Clients send feedback to server ( Yes / No + a free text )

I tried to look for best practices but I couldn't get accurate answer as it's pretty assumed that a server/client architecture leads to a J2EE-Android Java programming.

Here is my questions: [Which] of the following solutions is the best practice?

• Solution 1: 100% Android. Another tablet is acting like a server,
  centralizing content to display and gathering feedback.
  This tablet identifies the day comments and send by mail.
  Server only costs an extra tablet. No real server coding.

• Solution 2: Classic J2EE/Android Architecture. It requires an extra server unit ( rent a virtual one or buy a physical one ) and extra programming, but can provide JSP pages so a Web-App to display comments.
  A dedicated server seems to be more powerful. However, there are more and more powerful tablets now.

• Solution 3: non-J2EE (e.g. C#, PHP) + Android Architecture.