iCloud and dropbox file transfer

Not clear what you mean. On the PC, you put files in the local Dropbox folder and it automatically syncs to Dropbox in the cloud. Then on the iPad, you have to use an app that has Dropbox support to import the file(s) to itself. If you were to change the file on the iPad using that app, then you have to manually sync the file back to Dropbox, unless that app is designed to do that automatically.

Not sure if this answers your question. You also use "icloud" in the post title but don't discuss it in the post. It's somewhat the same process if using icloud - the important thing is that the app(s) used on the ipad have to be designed to use icloud, otherwise you can't sync files to icloud.

Not sure what you're asking. Sounds like you already transferred your files to your iPad 2 using Dropbox so not sure why you're asking "how can I transfer/copy all these files to my iPad 2...". I don't believe the Dropbox app on your iPad will sync changes made to your Dropbox account if that's what you're asking.

iCloud and Dropbox are complementary for the most part. I use both. iCloud is mostly a syncing and iOS backup service.

ICloud cannot be used to sync your Dropbox files. It can sync mail, calendars, contacts, bookmarks, etc., and iWork documents, but not the broad range of files that Dropbox allows you to save and access.