Ossau Iraty AOC can only be made in the French Basque area of Bearn and Iraty.
Only cheese made in that area can be legally called Ossau Iraty and receive the AOC or DOP seal.
In the past, different European nations have established their own protection of domain rules. The designation was only given to cheeses that had historical value and needed to be protected from competition of disgenuine cheese and counterfeits. The decree for a given cheese determine the area of production, animal and breed, animal feed, production method, aging period, size of the cheese, moisture and fat contents, etc. Makers of any of the cheeses that have such status are typically banded together in a consortium or co-op and market their cheeses together rather than competing against each other. Originally, each nation had a different name for it. In Italy is was DOP, in Spain it was DDO and France had AOC and AOP. Now the European Union is attempting to include all of the products under a single decree which is PDO and do away with the old system.
Carrefour - is a giant chain of European supermarkets, headquartered in France. They may distribute this cheese from Belgium, but the cheese is still made in the French Basque area.
Agour - is a major producer of Ossau Iraty AOC
Brebis - if just French for "sheep" (so there is no difference from your #1 and #2 examples).
Seems to me that you got a genuine, real Ossau Iraty AOC cheese!