Well, the only answers I can give you is wait until you've gained a few levels before tackling the EWC. He's not going anywhere, so you can just go on with your quest until you're strong enough. The EWC is a real bruiser, so really, don't try to take him on until you're fairly powerful.
As for who else can join, you'll see. Don't worry you haven't missed him/her yet. You still have a long way to go before you meet him/her
