I can help you with your first question (not doubt). I wish you had given us examples of "last" in a continuous tense, so I could be more specific.
As you are aware, "last" isn �t usually used in continuous tenses, but it isn �t impossible.
Our weekly meetings have been lasting longer and longer lately.
Although your example is also present perfect continuous, there �s a big difference. In your example, it is one event that is lasting, and the continuous doesn �t work there. It definitely has to be "has lasted". In my example, it is a number of events, each of them lasting longer, so as a group they "have been lasting longer".
The flavor of my chewing gum is lasting longer than usual today.
Since the present continuous is for things that are happening now, even "last" works in present continuous, if you are talking about a current situation.
This meeting is lasting too long. Let �s at least take a break.
Future continuous:
You will notice that our sessions will be lasting longer from now on.
When we use continuous tenses, it is usually to emphasize an activity over time - both the activity and the time involved being important. My last example above is used to emphasize the sessions themselves, as well as the time involved. I could have said, "You will notice that our sessions will last longer from now on", which is more giving simple information.
Bruce
