Hi Debbie, thank you so much for your questions. It can be confusing - in fact I just re-read the first piece you linked and realized it wasn't as clear as it could be, so we're doing some rewrites on the limitations of the student editions.
So on to your questions...
3. Actually, they can be upgraded at any time - but only to a commercial version and not to another education version.
4. Just check Adobe's discounted pricing for regular commercial upgrades - it's exactly the same for upgrades from academic software.
Hope this helps!