Having an older dog around is a constant reminder of what the end product should be. Monte knows that he is supposed to leave the puppy alone - no playing in the house. Just making eye contact with him is enough to remind him to SETTLE. He will either lie down at his PLACE or retreat to the bedroom. He now also has the advantage of getting up on the bed, which is still out of reach.
Cooper on the other hand is relentless. If I have told him once, I have told him a thousand times to leave Monte alone. He stops every time, but starts up as soon as my back is turned. Actually, I don't even have to turn my back, he will pause for a second and start up again. Monte resists, but can only tag the little guy biting his ear, throat, or leg for so long before he joins in.
The best solution that we have come up with for the time being (until Cooper's brain fully develops) is to perform a crate rotation. One dog in the crate at all times. It's not quite that bad. They usually settle down after a short time-out and we all can rest comfortably.