Paul,
First you may want to edit the email addresses you posted here. This is a public website and the spammers love to send robots to seek out new ones.
Your last question, yes, you can edit three blogs in one WLWriter desktop. At least I am currently doing two. Each will preserve its own look in Writer.
I think if I were approaching the three tasks you mention, I would first try to do them all in a single blog, "Blog" for the editorials, "Groups" for the forums and "Calendar" for the calendar. I have not done all of these, but in the ones I have done, it has been possible to set different "Permissions" for each thing. This would be easier to manage and also easier for your visitors to move among the segments. If it doesn't work out, you can always change it.