German Shepherd Puppy being too playfully aggressive with my other dogs, what to do?

I just got a 4 month old german shepherd puppy 4 days ago, he is kept in a pen most of the day, but I take him for 2 solid walks per day to let his energy out.

He's a great dog and I'm already seeing great progress, however when I introduced him to my dogs (an 8 year old german shepherd and a 3 year old Italian Mastiff) he becomes overly excited and goes right at their face with playful biting and he puts his paws on their face and tries to stand up on them.

Both my dogs have been very patient but are becoming quite irritated, the breeder who has been doing this for 30 years said supervise them but let the older ones dominate the pup so that he knows his limitations.

I'm a bit worried about that since the Mastiff is 170 lbs and can crush the little 30 lb german shepherd with one move.

So now what I do is leash the pup around them and slightly give the leash a tug when he displays this behavior. It seems to be marginally helping, but I'm not quite sure what to do.

I would appreciate any advice from past experiences.

Also my last question is a quick one, he tends to wake up at around 6-8 am and start crying to a point I think my neighbors are going to kill us (lol). We do not respond to the cries at all and are hoping it will stop soon, he has shown great progrerss with the crying but he still does for 1-2 hours, once when we come home from work from 6-8 and again at 6-8 in the morning. Should we continue to ignore this behavior and how long does this phase usually last? I rescued my other 2 dogs at about 8 months old and neither of them displayed this behavior,

Thank you

For the playing...

If there isn't any aggression going on, then I just let them work it out themselves. When we interfere, we tend to make things worse by causing confusion and worry. If there is a risk of him getting hurt, then I would separate them with gates, separate rooms, crates until the puppy is bigger. My dogs play very roughly with each other, and there's occasional snarkiness and grumbling if someone goes too far, but with the exception of Ares and Nyx together, my dogs work it out. Someone grumbles and whoever is being grumbled at learns to back off a bit.

For the crying, at his age, it could be that he needs to potty. What you could do in the mornings is set your alarm to go off before he's likely to start crying and take him out.

My shepherds and mals though have been known to wake up and start barking at sunrise ~sort of a "Come on!! It's time to do something!". If that's what he's doing, it's really a matter of ignoring him and darkening the room - pulling shades down. Maybe bring some fresh baked pies and cookies to the neighbors and tell them you're training the pup.

Actually the mastiff is reacting with growling and is now pawing at the dog to get him to stop.

My German Shepherd hasnt been push to the limit yet but I havent allowed the pup to push him too far.

Growling is how dogs tell each other they're pushing the boundaries.

There's also something that sounds a bit like a growl but is actually playful. How forceful is the mastiff with the pawing? Is he swiping at the dog playfully? Is he likely to step on the pup? What is the pup's response?

My dogs growl at each other and even turn their head and snap at each other if someone over steps their boundaries. If I step in, it only makes things worse. By leaving them alone, the dog being growled and snapped at backs off and learns what is and isn't allowed.

The only time I need to step in is with Nyx and Ares because Ares will warn with growls and lip curls and Nyx won't back off. Ares will then escalate to biting. I don't give any corrections. A leash tug can create more problems - the dog receiving it associates a correction with the other dog. I either separate them by moving one into another room or crating or I use obedience to give them time outs - a down stay for a few minutes so they can defuse. Or redirection to something else ~ redirecting Nyx to get her interacting with a more agreeable dog.