No password (initially) - you can always add one later, but if you want people to sign up and actually use the service, you should avoid it at first. I doubt many people will wander onto the site and feel inclined to post. The only issue will be comment spam.
Word press is good and free. Typepad is arguably better, but a) you'll have to learn it and b) it costs money...
I doubt many people use RSS, but you may as well use it as a platform as I suspect in a few years we'll all be pro's at using RSS