About your questions:
All NFT releases are limited versions.
NFT releases that have “Community Project” in the title are generated as ideas and concepts by the forum members and then submitted to the Captain. If Captain accepts the idea, he will create a NFT field out of this that then those members in that group can purchase.
How community projects are created:
A group of forum members simply comes together, or someone announces their idea and others join it, and then they work in a private mail chat on that idea.
You can create your own community project and invite others to join or join one of the community project announcement from others – but you need to be rather quick to join and then inside the group actively work on the project with others. Please study the community projects announcements here on the forum to get a feeling for how it works.
Once a NFT for a particular group has been made, the only way to acquire that particular NFT copy is through trading (forum) or buying (forum / Venly).