Dachshund and terrier, yes. And boy, are they a delicate and beautiful little dog!
The digging is a brand new thing, but the tumor could be invading some instinctive part of her brain that triggers the behavior...
Yes, they are, very dainty for all their resemblance to a the doberman pinscher! Both breeds are elegant in form, if not also a little intimidating when they want to be.