Hello again!
Me and Keppet have moved to England some months ago.
We're currently living with my fiancé's family and their dog, it's going really well I think.
Some background stuff.
Max: Max is my fiancés dog. He is a sweet 8 year old GSD. He is very calm and kind. He is very patient with my younger dog despite not having been around dogs much. He is "fixed".
Keppet: Keppet is my dog. She is almost 3 years old now and very energetic. She loves dogs and humans and goes crazy when she sees someone she knows. she's a submissive dog, or so it seems. She lies down when greeting other dogs etc.
The problem:
Ok, so there is no major problem. But I want some tips and help if I can get it.

Max has been an angel about Keppet moving inn. He lets her drink from his waterbowl, walk around in his area (the kitchen) and has even let her lie on his bed with him. He is very patient when she buggs him and all.
1.My dog is always trying to play. She likes to jump around, paw dogs in the face, rub faces and do the whole "we're fencing but using our mouths to do so" thing. Now. I am not entirely sure which of those is considered normal play, and which I should discourage. When she plays with young dogs they all seem as crazy as her. For now I try to discourage her from doing anything that seems to make another dog uncomfortable. She makes max uncomfortable by trying to play with him despite his calming signals. Even when he growls a little she doesn't get off him until I interfere. It seems to me that my interference makes Max a little more worried, because most times when they've gotten close to quarreling is while I separate them. At least that seems to be the case.
2. My dog gets way to energetic when my fiancé, his brother or his mother come home. If Keppet and Max are in the same room at the time, she goes crazy with excitement. Max gets happy too, but nervous because Keppet goes so crazy. I try to make her calm down. But what is the best way to teach her to greet people nicely? I have tried since she was a puppy, but obviously done it wrong.
3. The dogs like each other. In the mornings they will rub faces and some times kiss each other on the nose. They can lie down and relax in the same room, but if Keppet gets up while Max is lying down he starts whining and eventually gets up. Since Keppet came here, Max has grown more tolerant of her facerubbing, and bouncing etc.
4. We can't leave the two alone because of tension. We've never let the two run around together in the garden off-leash because we're worried they will fight.
*How could we help decrease tension?
*Some people say we should just let the dogs out together and let them work it out. But none of us feel like we understand dog signals enough for this to be a responsible course of action. What do you guys think we should do?