Yes. However, lab set-ups and individual PC settings can create minor difficulties with this. If you have experienced a problem with this, please contact the IT Services Help Desk.
Yes. Students can upload documents in the assignment, database and the forum activity, as long as you (as tutor) have set the activities to allow for this.
To get config values you would typically access the global $CFG object directly, which is automatically created by the core Moodle scripts. To set these "main" config values use set_config($name, $value). The values are stored in the Moodle "config" database table, but these functions take care of cacheing on your behalf, so you should always use these rather than fetching the records directly.
There is also a second table of config settings specifically for plugins ("config_plugin"). These are not automatically loaded into the $CFG object, so to fetch these you would use get_config($plugin, $name). To set them use set_config($name, $value, $plugin).
It is generally the case that there is nothing in Moodle that becomes set in stone. You can always go back and change things later. Resources and Activities in courses can be moved about at will. With editing on, look for the double arrow icon to the right of each resource/activity/block. Once you've clicked the double arrow icon your screen will change and you will see several blank boxes. Click on the blank box where you wish to move your resource/activity/block.
Yes, you can upload audio files into Moodle like any other file resource up to the maximum file size allowed for your Moodle site. You should ensure that the files have been recorded or re-encoded as MP3 files. Moodle contains a built-in player for MP3 files. If you need any help with this contact the LTU (firstname.lastname@example.org).