Wordpress with customizations

My client wants to have a website where collectors will be able to upload photos of their private collections and visitors will be able to view them. The process will be as follows: - A collector logs in - He goes to “New item upload” - He selects the category (Or categories if the item belongs to more than one) - He fills in the attributes that will appear according to the categories he selected - He uploads the images/images - The images automatically get the watermark “From the private collection of USERNAME” - He saves and the new item is uploaded and awaiting approval - An administrator checks for offensive images or missing text and approves the item that appears on the site. Example: Alex wants to upload a photo of an old coin. He selects the category “coins” and the attributes “value”, “date” and “county” (that are associated with the coin category) appear. He fills in 2€, 1955, Greece and then he uploads the two photos (front and back of the coin). The photos get watermarked “ from the private collection of Alex” and the item is saved pending approval. The visitor, can see all the collections without logging in, he can apply filters to see only the coins or only Alex’s collection etc. Note: The category/attribute section should be dynamic. That means that an administrator should be able to create new categories and assign new attributes to them. If for example we later decide that “coins” should also display the metal they are made from, we should be able to add “metal” as an attribute and assign it to the category “coins” from the admin menu. The website will be in Greek so everything must be translatable. The design should be simple but in a template that will have “room for corrections/changes”. It will be hosted on a VPS. I will provide the credentials.