Our family lost our miniature schnauzer (that had been part of our family 9 years) January of last year, and adopted another miniature schnauzer July of last year (he's been with us almost a year now!). We love miniature schnauzers! Like your family, my family has dog allergies, which are mitigated by adopting miniature schnauzers since they don't shed. However, we also shave both our dogs (Yorkie mix and mini schnauzer) every couple months, which pretty much eliminates the allergy problem. We've been doing this for 10 years, with both our mini schnauzers and our Yorkie mix. I really recommend it; it works well for our allergy problems, and they look pretty cute shaved!
Our first mini schnauzer was an incredibly smart dog. She was loyal and a sweetheart, loved to play with her rope toys but also loved to relax and cuddle. She would bark at anything outside, and any unexpected noise inside, but we got used to that. She was scared of balloons, vacuums, and pretty much any mechanical device bigger than her. She loved popcorn, peanuts, and pancakes (she could always figure out when we were making pancakes and would wait patiently by my mom's chair until she got her share). We still miss her.
Our more recently adopted mini schnauzer was the second dog we adopted after their older sister passed; our Yorkie mix was adopted about a month after we lost her. While the Yorkie mix is the younger and smaller dog in the house, he is the clear alpha dog. The mini schnauzer took to the Yorkie immediately; the feeling was not exactly mutual at the time but the Yorkie caught on quickly. Now, they're inseparable (our Yorkie doesn't love being outside, but our mini schnauzer does, so if the Yorkie comes inside before the mini schnauzer he'll wait by the door until our mini schnauzer comes inside too). They play fight all the time; neither one ever gets hurt but they prefer play fighting to most of their toys. They even share rawhide bones--we get the big one for the mini schnauzer and they work on it together until they get it down to two pieces. This mini schnauzer isn't quite as bright as his older sister was, but can be quite intelligent. He was reluctant when we adopted him, more than a little timid, but he was also a stray the ARL found on the street. It took him a while to warm up to all of us. However, he does remember the people he knows--my older brother and I are both in college, and he's not timid at all with us when we're home, and he loves my grandparents even though he rarely sees them. He would spend all his time playing and cuddling if he could--it really seems like this dog never sleeps, but he's only three years old and is very high-energy. He does play rough sometimes, and he does occasionally accidentally sit on our Yorkie mix, since the Yorkie is so much smaller than him. He and our Yorkie mix are both scared of vacuum cleaners, lawn mowers, balloons, brooms, mops, and virtually anything else nonhuman that's bigger than them. Our mini schnauzer won't do anything without our Yorkie mix: he won't even come in the house if the Yorkie isn't with him or already inside, and when we walk them separately, he runs back and forth between doors to our house and barks, cries, and whines until the Yorkie comes back. They don't have jealousy problems, but if one of us is holding or petting one dog the other almost always comes over for some holding/petting as well. He constantly craves attention, whether it's from us or from our Yorkie, which he gets all the time anyway. If he's not getting attention, he'll go from person to person till he finds someone to pet him, and if he can't find anyone he'll start up a play fight with our Yorkie. When we adopted him, we were looking for a miniature schnauzer in particular, and we are very happy with him!
As far as adopting goes, all three of the dogs we've adopted have come from the Animal Rescue League. When we were looking for a dog, we would check the website several times a day looking for a dog that fit our specific breed needs, and would visit the ARL almost daily in case they had brought in a dog that hadn't made it onto the website. In our area, young dogs of non-shedding breeds get adopted almost immediately, so we'd be constantly looking. We adopted our current mini schnauzer quite literally the day the ARL listed him as available for adoption: we saw him online that morning and I went to two different locations looking for him (they moved him without listing it on the website) before we finally found him; we brought him home later that day. We had virtually the same situation with our Yorkie mix. If you have an ARL location in your area, I would suggest doing this: it gets tiring at times, but is totally worth it when you find the perfect dog for your family.
Good luck with your search!