1. Our themes are not encrypted, so you are free to modify files accordingly to suit your needs. Basically if you have the knowledge to make such changes, there is no reason why you cannot do so.
2. Yes you can create additional pages in the
wp-admin if you wish, and have these appear in the main menu.
3. This may require some customization in order for the correct information to appear, but technically, yes, it can be done.
4. AppThemes does not officially support third party plugins or customizations, so in terms of plugins specifically, we cannot guarantee they will be compatible with the theme.
As mentioned in point .1, yes technically you can make whatever changes you wish to make with some customization of the theme.