I believe the blog entry is more updated information. The offline help file also states:
"Communicator Web Access can be collocated as specified in the table, but it is not recommended that it be collocated with any other server role."
It appears that FE and CWA collocation is possible, but not recommended as the Web Components role and CWA both use the default IIS site and some manual configuration changes would be needed to get them to play nice together.
Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS