Via route

I have a question. 

I am a Belgian airline and want to fly from Brussels to Charlotte via Reykjavik. As Iceland and Belgium are both in the EU treaty, passengers should be able to board in Iceland to go to the US right?

I am using a B757-200IGW for this flight and can not fly direct because the distance is too long.

Now if I make this route, the balls near the pax icon are coloured red for the Iceland - USA part. What does this mean?

No, as a Belgian airlines you don't have traffic right for KEF-CLT. That's the reason for the red dot.

Of course passengers can still book BRU-KEF-CLT, but the question remains, how competitive this offer is. So better check the ORS.

The EU treaty only gives you traffic rights within its member states, not to non-member states. So as a Belgian airline, you can fly between any member states (e.g. Iceland-Germany, Finland-Spain), but you can't fly to the US except direct flights from Belgium.

I might have a question on that subject, i get red lights when i do a SYD-AKL-LAX  in the real world this should be possible.  As AUS and NewZealand have given each other the 5th, 7th and 8th freedom.  But i still get red on the segment AKL-LAX, is this false or can i fly this.

With these rights i should be able to fly AKL-LAX with out a via flight

In AS, on older servers, an AU and NZ airlines can fly in each other country on domestic routes but not on international ones.

But why have the 5,7,8th freedom if it not possible?

Specific freedoms of air implemented in real world on country-by-country basis cannot be implemented in AS because of technical limitations. Most European airlines in real life could take advantage of 5th freedom rights on EU-USA-X afforded to them by the USA-EU open skies agreement. But in AS this is not possible.