Rating on each of the photos listed on the PHOTO tab. Rating should be stored on a database. Rating should only be posted once per photo, per user.

This should be fairly easy to add as you could use a template override to handle the display. Then triggers to handle the storage.

Commenting on each photo: Comments should be stored on a database. The comments should show when you see the image in the lightbox. We want to be able to delete comments on frontend for moderators only.

Can probably use a 3rd party commenting extension to handle this for quick implementation. A template override could be used to add whatever code the commenting extension needed.

Organizing photos in albums from the PHOTO tab: let the moderators create folders, create embedded folders, and upload files. Also, let the registered users of the group navigate the folders, and choose to which folder upload their image on the upload form. Registered users should not be able to create folders. Folder renaming is necesary and permissions need to be edited on Joomla! backend.

This is a massive massive change. This would require a complete rewrite to the upload handling, frontend display, new backend display, and storage.

We need users to be able to upload as much images as they want at once! In this step, we want to implement www.filepicker.io It needs to generate a thumbnail size (for list view), a large image (for web view) and a full resolution image (for download). Sizes of the images should be set on the backend of the plugin management. A "download full res/ web version" button should exist for moderators up.

This maybe a bit more doable by extending the edit usage to have more upload inputs and during save to loop the inputs like kind of what is done with the Invites feature when sending to multiple users.

Some of this is planned after CB 2.0 like commenting, folders, and better uploading capabilities, but that isn't until after CB 2.0 releases so there is no timeframe available.

I suggest posting your request to sites like joomlancers or freelancers to see if someone can bid on your project, but for 3 you likely will need to increase your budget.

Maybe a better approach is to simply use a 3rd party Photo extension and simply link to it and maybe use CB Auto Actions to create categories in it automatically when creating a Group. Then use the 3rd party Photo extension to handle all this as many of them already have the features you want.