1 - in my view (and this is purely my guess), the new engine would work well for a PoN2. Not least it is far easier to write branching decisions and events - something that is very hard in the current game script. Also in testing Empires, I remain really impressed at its speed - so the processing/slow turn issue should be removed.
Also the new game engine is happier with a dynamic world, even if you created a constrained design (so no world conquests Paradox style)
Is a new PoN at the top of the list - don't think so. Pocus has been clear that the goal is to bed the new game engine down with simpler more straightforward games so you might see say a 7 Years War game or the American Civil war first.
Stressing this is just me, but I could see PoN working brilliantly on the new game engine - most of the research is done, the key game play concepts are well tested. But it would still be a major piece of work to do and balance etc.
2. not sure what you mean? But being pragmatic, the last patch is it for PoN. A pity, but it does clear up some of the long standing issues but I doubt that anything that would need work on the .exe will be addressed.