Indeed, you will retain all the publishing and copyrights !
The only thing we will need from you is the permission to use your content and make it available offline on Neovel.
About the exclusivity, we do not want to include any in this adventure with you! Neovel is mostly a diffusion facility and a possible source of income for the authors/translators, nothing more (we are not a publishing house). That way, you will be able to diffuse your novels wherever you want outside of Neovel.
The same, you will be able to add, modify, remove novels from Neovel, (etc..) whenever you want. Just send us a message to tell us that you are doing it (especially for the modifications or when you intend to remove a novel).