Any pre-release information will be sketchy so the Region B status over at bluray-disc.de is not a confirmation since they haven't actually tested any of the discs yet, they are simply being cautious. It is most likely that the first four discs (X-men, X2, Last Stand and Wolverine) are identical to the previous releases and then all those should be Region A compatible (the first three being region-free and Wolverine being region A/B). That leaves us with First Class as unconfirmed at this stage.
Ultimately we won't know for sure until the actual discs in this set has been released and physically verified.
It depends a lot with the studio releasing the BD in question and whether they have licensed/sourced out the distribution to others. Watchmen is a Warner release and they along with Universal are known to issue BDs that are pretty much all open to all regions (one or two exceptions exist with each of these studios but 99.9% of their titles are open to all regions).
The X-men films are issued by Fox and region status with any of their releases has been and continue to be a crap shoot, in the end you won't know until the disc has been released and the disc has been tested and confirmed. Sony tends to be region-free most of the time (titles they have sourced out to Image Entertainment however are region locked). Disney is another company which flip-flops region locking their discs or not. Paramount also chooses to lock certain titles. Anchor Bay started out with all-region BD titles but started locking all titles as of last year. StudioCanal is another that flip-flops regarding region-locking from one title to another. Criterion titles are all locked. Smaller distributors in Europe largely tend to lock titles. So, no, blu-rays are not "sort of" region-free.