Your voice is getting louder!!!

Not sure how you're rotating, but it seems to be working well.

When you bring the students in for closure, have them put away the equipment first.  1-2 minutes is generally good. Often, telling them they'll go in as soon as you finish your speech will help the kids to put away the equipment faster.

Pickleball Volleying

Keep the students up on the non-volley zone.

Make sure they're clear about one bounce or volley.

Use words and phrases like, "block," "catch the ball on the paddle," etc., so they can understand that a swing is not always necessary.

Racket position is also important in that it should be up in a neutral position and not down below the waist and/or to either side.

Pickleball, second day

A good check point for a forehand drive is to have them touch beyond the opposite shoulder with the paddle. Check points are important for evaluation and this is one readily observed.

When kids have to wait to play, I'd have them always sit facing the action.

When you're doing a mass substitution, I'd get everyone's attention and make sure they leave the rackets and balls on the floor.

As you become skilled at teaching striking skills, you'll definitely feel more comfortable in passing on key landmarks that you're looking for and evaluating the students with respect to those landmarks.

Sometimes, it's not enough to tell the students to follow through. Landmarks and checkpoints may be needed.

Pickleball after lunch with challenging class

The boys that didn't do the warm-up can be called on that. Either with direct challenge, but certainly, I would make them wait to play if they hadn't warmed up.
Despite the behavioral issues in this class, they do like to compete.  Use that to your advantage, although their avoidance of the warm-up needs to be addressed. I was really looking forward to them trying that.
There can be a case made for keeping students with control issues in the game as much as possible. When they are occupied, they are less likely to be behavioral issues. As long as it doesn't impact on others' playing time.

Pickleball, 1st day of teaching

Make sure you are continually directing your voice to the biggest volume of the room, using the most advantageous position.
Unfortunately, when partners are throwing balls to each other for drilling, care has to be taken so that the throws are effective. I find sometimes I have to stop class for that as much as for general skills discussion. I've tried to impress upon the students myself about the importance of a good throw, sometime to no avail.
Also, with regards to throwing to the partners, make sure they step to the correct foot when they throw. Hopefully, there'll be carryover to forehand shots.
Make sure the students know whether you will rotate them or give them a specific number upon which they'll switch roles. I used to announce switches. I've gone to letting the students count and switch.
Students need to hear the importance of  the hips and legs with throwing and striking movements. Draw parallels with other similar movements.
With mass substitutions, make sure that all students have played, by asking those sitting out.