I would suggest an order of which guilds run which weeks, and leave it to them what to base their classes around.
Thursday and Saturday should both work for me, depending on the timing.
The suggested topics were only meant to provide a starting ground. Not be a solid hardcore rigid guideline from which you had to work. Some topics will be unnecessary to cover with the people in attendance while others will generate more questions and time devoted to them. Everyone would have to tailor their lessons to their audience to some extent. Which is a roundabout way to say that yes, people would be able to determine somethings on their own, but you also want a standard set of things to cover as well. Maybe also best practices shared between guilds and teachers.
In the past I've seen effective use of multiple teachers during one class where each talks about the things that they are more comfortable with and think they can provide a bit more flair to that particular discussion. Like a priest might discuss how to use spells while RPing by toggling on the shadowform or using mind vision. Or a mage would cast mage ward to create the illusion of pulling arcane energies from the surrounding environment to use for a spell. While a warrior talked about godmodding by heaving a heavy axe at a person and splitting them in twain.
I think it would be great to do it that way. With the guilds providing a teacher each to do those discussions. Then you could rotate the topics so that no one is forced to do the really boring topics each and every week. I don't think you'll need each guild present each week but since we have an odd number so far it might be useful to do it that way or set up a 3 up 2 down rotation.
So far the guilds I've seen an interest from on the forums are:
Pia Presidium
Terra Incognita
Conclave
The Ebon Sanction
Stormwind City Watch
What time Saturday would be best for everyone?