Hi
I worked with Couchbase Lite, its awesome for working with online and offline Applications. but i have a doubt about Couchbase Lite work only in online mode. i mean without storing documents in iPhone storage.
For anything that cannot be replicated and persisted to Couchbase Lite, you can register views on Sync Gateway and query them with the REST API http://developer.couchbase.com/documentation/mobile/1.1.0/develop/guides/sync-gateway/accessing-cb-views/creating-and-using-a-view/index.html
James