In regards to your questions please see the following.
3. The license will work with any one of the 4 flavors. You are not limited to which one you utilize. You can share the database between the portable and installed version without issue as well. The license is per user, not machine, so you can install on multiple machines and carry on multiple portable devices.
4. Yes, see #3 response. The license data is embedded into the database for your usage and transferring between flavors of the software.