Well if their baseball leagues turn out anything like their football leagues of the past two years, I would stay FAR away from Fox.
And yes, you can boot people from Yahoo.
You can contact their support staff to remove an inactive member and have them replaced.
CBS is o.k., but unless it has changed, it's a weekly lineup site.
I was thinking of returning to ESPN for a trial, but it's hard to stomach all the scripts their site throws at you.