Boykin Spaniels are really neat little dogs and would certainly be more than capable of the exercise you mentioned.
On the mutt side, I've got a 1/2 Boston 1/2 shih tzu that is the cutest and toughest little dog ever. Perfect temperament - loyal but not needy, friendly to other dogs and all people. She's our farm manager. Our Corgi is evil and the Great Dane is so low key that little Izzy has to pick up all the slack.
If you believe everything you read, better not read. -- Japanese Proverb
Well, OP said she had & likes Schnauzers (which gross me out) so the Scottie beard wouldn't be a problem.
I've seen Xolos at coursing tests and they're active and fun.
If you like Cockers but SO doesn't, go with the original Cocker Spaniel, now called the English Cocker. They're beautiful and active and IME not nearly as dumb with bulgy eyes as the American Cockers have become.
I'll throw my two cents in for the Scotties since I have two. I'm not sure if my experience is different because I have two, or if mine are just oddities.
Mine are brother and sister, same litter (learn from my mistake, don't get 2 puppies at the same time, it's chaos). Scots tend to bond to their close family, and can be pretty standoffish with anyone else. Mine however have bonded to each other (and the male to us, female does her own thing), and thus when separated, will howl like tiny demons. But they love everybody (don't know if this is because they're bonded to each other or what), regardless of size, anyone they see needs to be investigated and licked IMMEDIATELY!
They are completely fearless of anything, including other dogs. I had to pull them off a doberman yesterday, and have seen them tag team pits in the dog park, but it's always attempts to play, never aggression (I have seen female roll over and submit to chihuahuas). They have to have noisy, growly, play fights with each other at least 6 times a day, because if they are awake they are playing (or boy is on one of our laps, he likes to watch tv and youtube videos of westminster). They will chase and eat anything that moves, including leaves and especially bugs. Female is a barker, male is quiet.
They don't shed much, but they have to be groomed pretty regularly (I do haircuts once a month, takes me an hour per dog to do it really well). The girl likes to blow bubbles in her water bowl and then rub her soaking wet beard on the couch. If you grow out the furnishings (belly hair) it catches dirt on walks (2 miles is no problem at all) and that also ends up on the couch.
They are dumb, kind of hard to train, and easily distracted (yet focus like a laser on the distraction). If they're not convinced that you are the boss, they will walk all over you (both literally and figuratively, mine respect me, but think the DH belongs to them). If you can put up with that, they are loyal, tough as nails, and freaking adorable (and pretty dignified looking when not chasing grasshoppers). I love my little idiots to bits and wouldn't trade them for anything.