Facebook API, Dropbox API, connection to my website

Project Description:
Hi,

i need 4 features for my existing website.

1. login via Facebook on my website (like here on freelancer.com)
2. postings-sharing on Facebook, similar to http://9gag.com/gag/6494486. You can select if you share your postings on Facebook
3. is it possible to create Facebook groups from my homepage? on my page users should be able to create facebook groups automatically. And being the admin of that facebook group
3. On my website users can download and upload files. I need a connection to Dropbox, so that users can download files directly to their dropbox folder, or upload directly from dropbox to my website.
Workflow:
User subscribes an object on my website -> a folder will be created automatically on his dropbox folder with that object name --> the files will be synchronized from my website to the users dropbox folder. Also a download link entry must be created on the website, so that other users can download that file from the website. The users who subscribed that object will get the files automatically to their dropbox folders.
4. Upload function should be optimized on my website using html5. You can take the following example and adapt it to my webpage: http://demo.tutorialzine.com/2011/09/html5-file-upload-jquery-php/
5. Later on if the Dropbox API works well then i need the same with Google Drive API and other cloud solution API's)

PS: My website has been developed in LAMP, with CakePHP framework, mysql database

For detailled questions do not hesitate pls.