Nightfall vs GW Core Changes

Question is:

What changes will take effect for all of GuildWars and which will be only for Nightfall campaign?

As we saw with Factions and the inventory upgrade, it's possible for them to separate components by campaigns. I'm particularly interested to know if the skill templates will be available throughout the campaigns, regardless of buying Nightfall or not. The second point of interest being the Heroes in the new battle isles. I would imagine that those would be for anyone, and as such access to the Heroes would have to follow, though I'm pretty sure that pve Heroes will be limited to Elona.

IN PC gamer it says that Regardless of Owning NF or not, you will be randomly attacked by spirits in Prophecies and Factions.

There will also be new Islands in the Battle Islands, So I'm assuming that only Hero's Will be available in those islands.

Yes, read the article on PC Gamer, but even that was vague regarding the skill templates

This has made me very curious as to how they will implement this. It would be interesting (and fun) to be in a Fort Aspenwood mission only to have a portal open up out of nowhere and 20 Grasps come running out attacking both sides.

Now before people respond with "It's already happened in TpPK and the Dragon Festival" past events. I believe this will be random events after Nightfalls Release.

The only problem with that is that the load time as we start the FA map will give the game away.