From a player's perspective that has played with younger kids:
2nd the idea that you are the GM. Another adult needs to be the parent/guardian. The 2nd adult handles the "I want a drink/snack." "I need to pee..." "I am bored..." stuff. A GM doing parenting stuff is a distracted GM.
I'm sorry but I have to be completely blunt: this is TERRIBLE advice. Do not do this. This will completely undermine your authority. Chaos will ensue. Speaking here from decades of experience as a DM, parent, running D&D Club at a school, and especially as a teacher. If you're in charge, be in charge and responsible. Your primary responsibility is ALWAYS the welfare of the kids. If you're not up to it, don't do it.
This is like suggesting a teacher teach a lesson while a parent minds the children's behaviour, or a coach run a practice with the help of a minder, etc. Disastrous.
Attention span. Younger generally equals shorter. Don't spend a lot of time on prep at the table. Try to get that done prior. If you spend 20 minutes on one kid's character, good chance some of the rest will give up.
Be prepared, on the other hand, is always excellent advice!
Phones/devices. Some will have them. Best if they can be turned off and handed to the Parenting adult. Otherwise you are contending with the device for the kid's attention while the others are getting bored.
Agreed, except for the parent part. You're the parenting adult, so tell them to put their devices away (unless using DDB, though with this age I would go with simple character sheets because they will almost inevitably be drawn to their device for non-gameplay reasons). Don't make it a debate.
Discuss with the parents about content. Adjust your game for the most G rated common denominator.
I wouldn't ever discuss it with the parents unless they have questions, but I'm a trained and experienced teacher, so I have confidence in my ability to gauge what is appropriate. If unsure, asking parents is one option, but you'll get a ton of different answers and often they know a lot less than they think they do.
Be prepared to deal with kids that go more R rated then you planned.
"No" and "Stop" are very effective. Delivered kindly but firmly. And then move on. Don't belabour the issue and give it life.
While you are talking with parents, establish what the parents are expecting for their money.
What? No. Tell them what they are getting for their money. In advance. Know your parameters in advance and be firm. Parents are always trying to find exceptions and assert control.
Get some cheap dice sets to loan/give the kids. Also a notepad and pencil.
Great suggestions!
Maybe even some colored pencils. Decent chance that at least one of the kids will want to draw out a character or scene. Gives the kid something game related to do when others have the spotlight.
Eh...this is not much better than handing them a phone, for some kids. I would take the coloured pencils away when you aren't specifically doing an art exercise, like illustrating their characters.