You make a fairly interesting case. I don't know the intricacies of international contract law, but I can imagine that a reasonable interpretation of 'exclusive access' in this industry would mean 'to the exclusion of the general public', with the exception of influencers and perhaps some other groups such as family members. Alternatively, developers can easily circumvent this by offering those groups a different version with a different name. I would be interested to see some actual case law dealing with this sort of problem.
To be honest, I'm not sure there has ever been legal action taken for an issue such as this. Due to a low award that could potentially be had (at most the cost of the game - in this case) from a case such as this suggests that pursuing legal action would be much more costly than any award even if a case is won. It would take a class-action suit to make a case such as this even remotely worth pursing. I would tend to believe that Frontier and their team of attorneys already know this.
What I'd like to see from Frontier is simply a public apology for creating the confusion and a promise of withholding words or phrases that are seemingly misleading in future game releases. I purchased the Deluxe Edition in large part because of the alleged exclusive beta access and to a smaller degree because of the 3 animals that are supposed to be limited to the Deluxe Edition. We'll see in the future if Frontier sells those 3 animals within a dlc or adds them to the base game. Which would be another breach of contract if they do. As for now I have every intention on playing and enjoying the game. However, I might refrain from purchasing games in the future where sales promises might easily be broken or seem misleading.