I will do my best to help.
Vomiting can be caused by dozens of things: infections, parasites, food sensitivity, eating something they shouldn't (especially puppies). Schnauzers as a breed are prone to pancreatitis
, but he is a little young to have that.
The mucus you saw in his may indicate an infection moving through, first making him vomit then getting to his colon and causing him to have the accident in his crate.Urinating
without warning can be a sign of a bladder infection.
If his gums look pink, if he does not have a fever (normal rectal temp is between 101 and 102), if he will eat, I am not too worried about him, but would keep monitoring and maybe feeding
a bland diet like boiled chicken
and rice for a day or so before getting him back on his puppy food.
If the mucus continues in his stool, I would have a sample checked for parasites.
Let me know what else I can answer or help with.