Thank you all for the support of this project! Here are my thoughts after using it for two weeks.
The 5 inch DSI screen is great to use. While it is smaller than some present-day phones, I would compare the usage of it to an iPad. It is very responsive, and Chromium has multi-touch build in. However, I could not get a right click button outside of Chromium.
I wanted to be able to use the HDMI ports along with the 5 inch screen. I have not been able to achieve this, yet. It might be a problem with my Raspberry Pi, not others.
I did not include speakers or a microphone with this project. I wanted the project to be simple, and I felt that the headphone jack would be all that I needed. While it is not the best, it gets the job done. When I make a second version of the tablet, it will definitely include better audio I/O.
I wanted this project to be as simple as possible. I did not solder anything. A downside of this was the thickness of the tablet. However, I did not feel that it was too bulky. The device stands up on its own, at an angle that is great to watch videos.
I have been working on other projects, but my plan is to make the device more modular.
What is that GUI you are using in the first image?