Blu-ray players support 7.1 audio formats and high-quality, lossless surround sound. While your high-def disc player and receiver may be able to decode these new surround sound formats, not all discs you play will take advantage of them.
You can choose to store your files on your Chromebook or online with a cloud-based file storage service like Google Drive. With Google Drive, your data is stored in Google's highly secure data centers. The Terms of Service make clear that what belongs to you stays yours..
The system files will most likely be in the root directory of the internal storage. The Android folder you're seeing is on the internal storage /sdcard/Android and holds game data. The system files will be visible for you but without root access to your phone, you will not be able to delete or modify them.