I'd say 'yay' to your 1, 2, & 3.
As for the Scottish/Reykjavik question, I’ll check the latest jepp chart.
I work the airspace so if Jepp is saying you get a clearance from Scottish, their document is wrong
I've found too, that query is usually met with "you can expect further with the next sector"
This will usually be given when you are going to another Control Centre's airspace. The initial controller will be able to clear you to a waypoint which is either within his airspace or one which is in the next Centre's airspace but is known or is routinely used for procedures between the ATC units. What the transferring controller may not have knowledge of is the routeing required further down the line, in airspace which he has no detailed knowledge of (and is not required to).
For example, you may originally have planned to be routeing via XYZ in my airspace, but are given a different routeing when airborne (e.g. coming in from Oceanic airspace) which now takes you to ABC in my airspace. If I can't get you back to XYZ, or perhaps think that getting you back to XYZ may be a less logical or efficient route from your position than that to ABC (which of course was not on your original plan) then I'll clear you as far as I can to either the boundary of my airspace on a new route, or more usually to a waypoint within the next Centre's airspace which accords with your new track.
What I probably don't know, without a bit of time consuming detective work, is where your original route was and how it would be best to rejoin it in the next Centre's airspace. I also have no knowledge of the various procedures and conditions which apply in that next piece of airspace. If I make a best guess and pass you a route I think might be alright, I might be setting someone up for an incident once you leave my airspace. So, if I can, I'll ask the next Centre where they want you to route after my last waypoint, but this may not always be possible if the traffic is busy or my workload is high. The same things might also be happening to the next Centre controller and he'll want to save time (RT and telephone) by passing it to you on contact, rather than relay it to me, have me read it back to him, and then rely on me to relay it to you. So that's why sometimes you'll get a message that the next sector will give you onward clearance.
