The other think Chelsea is teaching the kids simple tricks like not lifting their arms up in the air when the puppy runs up to them - this can encourage jumping up. It can all be fun and you can do it all together with the kids and pup.
Watch them together and see if there's anything that the kids play or do that sets the pup off. Then you might see ways that you can easily wind that situation down a little. Most jumping and mouthing happens when things are getting a little over excited.