All understandable. Tornado-dog still gets overstimulated at times (JRTs thrive at overstimulation) and it's easy to get frustrated by it. All we can do is offer suggestions when the person is open to it and back off when they get frustrated. You might suggest before the walk "hey, let's try starting with a bit of obedience when we first get to the field and see if that helps calm everyone down".
Thanks once again toedtoes, that sounds like a good idea, see if they will all do it together. To be honest I think they really need to spend a little more time together so she is not so hyped up when they do meet and then she should hopefully think oh it’s only them and they don’t have me jumping all over them
She is still very young to sustain control for more than a few minutes. Puppies love to do little acts of obedience for a reward but don't have enough self-control to be able to keep it up. I must say that if she was mine I would have her on a flat half-inch collar as well as her harness - and use a double-ended training lead to connect them. This would give your son an additional aid to turn her head, and help to redirect her attention back on to him when she starts to become over-stimulated.
Spending more time together won't lessen the hyperness. It's her belief that other dogs are always for play time that gets her excited, so more time playing with your dogs just reinforces that idea. On the flipside, reducing the contact can cause stress and anxiety when they do get together. I agree that at her age, she won't have the ability to do a lot of obedience. Simply redirecting her to focus on the world around her rather than on Buddy and Beau will help teach her calmness. Intersperse obedience as you walk, just a sit here and there, look at me, etc. With a long lead, your son can start teaching her to "wait for me". Let her run ahead and whenever they reach a turn or drop in the trail or a wet area (specifically points where he would lose sight of her if she kept going, etc), then tell her " wait for me" and pull the lead in so she can't go any farther until he reaches her, then he can loosen the lead again. That may help her learn to focus on him more. Another thing you might try since it sounds like Beau isn't frustrated by her, is to use a double lead to connect her to Beau. Then use Beau's obedience skills to basically force her to obey. I did that with several of my dogs over the years. Attaching the hyper puppy to the well behaved older dog. The puupy found that when I called them back, it wasn't optional because the other dog obeyed. I like using two leash extenders rather than an actual coupler so that I can detach one dog and use the extension as a short lead (I clip the ends together so it becomes a loop) if I need to separate them for any reason. That could slow Beau down a bit, keep her away from Buddy, AND give her a bit more freedom while retaining at least some control. I did the above two ideas together when Bat-dog was a puppy. I hooked her up to Moose-dog and let them run ahead. Whenever they reached a spot in the path that I didn't want them going past, I called them both back. Moose-dog, being a perfect dog, would come back and Bat-dog had no choice but to come along with him. And Moose-dog learned by getting attached to his big sister, Dog, who was a perfect dog. After a while, they would automatically stop at a turn or fork in the path until I caught up with them and then off they'd go again.