I'm sure you'll be off to a running start with that set. As far as motors go, it includes 1 DC motor, 1 servo, 1 vibration motor and 1 fan. The DC motors are best for projects that require rotational movement such as cars, ferris wheels and art bots.
If they both want to do projects like that at the same time, consider adding another DC motor to your purchase.
As far as the cloudBit goes... I normally would recommend the cloudBit Starter Kit, but you would have a lot of overlap in bits with the Student Set. So, maybe you'd prefer to buy the cloudBit on it's own - don't worry, it still would come with a usb power and an adapter cable. However, unless it's in the bundle, it does not come with mounting boards. I recommend you get either mounting boards, brick adapters (use 'em with legos), or shoes (sticky, velcro, or magnet) to keep your cloudBit powered.
I hope that's helpful. Please let us know what you all MAKE!