Does your BJJ gym train how to properly complete single and double legs? How to sprawl? That and a decent headlock is a good start for kids. You should be able to practice that with them. Just drill the proper way to sprawl over and over. And how to shoot over and over. Just committing the act of doing everything you can not to go on your back after being taken down takes a while to commit to muscle memory.
I know there’s a wide spectrum of training styles at the millions of BJJ schools in this country, but I had a hard time finding one that properly trained take down and take down defense. 90% of the time we would start from the knees, which made no sense to me because that’s not how fights or competitions start or anything resembling any real combat sport situation, and if you don’t know if you can even get your opponent down there why always start like that? Are you going to drop to your knees and lay on your back on some concrete in a self defense situation? I ended up going with Sambo training because it was the perfect way to transition my wrestling into submissions. If you live in a city you’re kids might like some Sambo once they get their footing in wrestling.