Sounds like a good opportunity many would be interested in. It also sounds like you have a good handle on leading it. Way to go!

I'd like to make a couple of suggestions. Don't dispense with the introductions (but do keep them brief, of course). Too often classes are thought to be only for the dispensing of information, whereas the greatest value in most classes is in developing a learning community, for however short a time. The acknowledgement of each individual's differences and purposes for being there not only builds community (and the best learning occurs when people feel good about and trust each other) but allows the teacher to tailor the instruction.

And don't forget that some singing traditions ask for non-classical vocal production. For example, Irish sean nos singers frequently close the sounding consonants, like n or r; or the Balkan raucous-sounding full-throated singing, or Tuvan throat singing.

If qualifications make any difference, I am a classically trained musician (and vocalist) who now sings mostly in the sean nos (old style) and have taught school for 18 years.

Good luck with your future workshops! (And it sounds like you have a valuable assistant!)

David