Not for sure on the split screen online with same console users. I think that may be something new they featured in Black Ops.
Everytime I hop on I have no problem finding matches, even on regular rush mode (with the larger teams). If you're not fully enjoying Black Ops I would highly recommend this game. One reason I really enjoy it is because I'm not really good at the quick twitch games getting kills, and in this game I can contribute to my team winning in other ways besides just kills...or lack thereof, lol.