I didn't reply to this post at first, because it made me really tired out to read it.
You need to set clear parameters for your class.
1. If it's a two hour class, allow for 15 minute clean-up within that time.
2. Write out a course outline e.g. week one centering. Week 2 cylinders. 3. Bowls. 4. Trimming. 5. Handles,etc.
3. I also always began with hand building. If people don't like throwing, they can always go back to hand building.
If it is a 10 week course, you should not be accepting students in the middle.
If it is a year long course, you could accept the newbies at the beginning of the month, or some agreed upon time with your boss.
I taught evening pottery classes at our city art gallery for 8 years. I have now been teaching art with a B. Ed for 27 years, I earned my degree while teaching at the art gallery.
The flaw with teaching evening classes, is that it is a bit thankless. You never get past the beginning stage, then the class is over and you get a new batch. Like Sysefas. The guy pushing the rock up the hill. Eventually you get tired, and the rock rolls back and crushes you. Too synical?