Re: Puppy playing. Please advise
I don't think that the schnauzer mix is a good dog to be playing with, it doesn't seem to be playful or puppy-tolerant and it could turn ugly against your pup.
BUT, I also disagree that puppies shouldn't be playing with adult dogs. Well-behaved, well-socialized adults are great for puppies to play with! They can play and still teach manners. My two don't care about having their faces/feet/tail/ears nipped or pulled on by a puppy. In general, adult dogs give puppies a 'pass' to be puppies when they're young and tolerate behavior that they would never tolerate from an adult dog. A well-adjusted adult dog may not necessarily be a playmate to a puppy, but they certainly shouldn't act aggressively to a puppy. A correction for being too rough or annoying is generally okay, aggression is not.
That means only dogs you know and are comfortable with should be allowed to play with your puppy. Avoid dog parks with a puppy, there are too many variables and you don't want a bad experience there. The puppy classes are great, as long as the other puppies aren't bad. If you have friends with good dogs have a careful introduction and maybe have playdates if they do well.
So, I would keep her away from the schnauzer mix because it does not sound like it will tolerate puppy antics and could turn out badly, but that doesn't mean she should be kept away from adult dogs altogether. Definitely keep on working on leash manners so she doesn't try to run up to other dogs, she is still young though and it will take awhile to learn.