as a co-founder of Couchbase I should be able to give you a clearer understanding. I’ll take your questions in turn.
1) Correct. Couchbase Server is not CouchDB. It sacrifices some of the neat things CouchDB does (HTTP interface, master/master replication) so it can do other neat things (sub-millisecond latency, gigantic clusters.) In the long long run, we’d like to get back high-performance versions of the features we had to drop. For now, we are building the fastest most reliable NoSQL database (yay) but it’s not answering the same use cases as CouchDB.
2) Maybe I just answered that? More info about Couchbase Server is here: http://www.couchbase.com/couchbase-server/overview
3) Couchbase continues to invest in mobile technology. We have well tested implementations available for Android and iOS. These are based on Apache CouchDB, so they will have the feature set you are looking for. Visit here to download them: http://www.couchbase.com/wiki/display/couchbase/Couchbase+Mobile+Syncpoint (see links for iOS and Android on that page)
Going forward, we are focussing on light-weight alternatives to actually running CouchDB-based code on the device. To get CouchDB to run on the device requires the Erlang virtual machine. While it is lightweight and respectful of battery life (for a VM), it is still a VM. So we are building more lightweight sync and storage engines for mobile. TouchDB for iOS can sync with Apache CouchDB. We also have a similar project for Android. If I were starting a new project, I’d take a look at these.