#4 Dachshunds are intelligent dogs with an independent nature and playful soul. Therefore, he is often a prankster. Be strict and consistent when training.
#5 Because they were bred to hunt, their behavior can be reminiscent of this.
They were designed to dig into badger burrows, and that same instinct may lead them to dig up your dahlias instead. They were bred to be persistent when hunting and because of this instinct, they may be constantly begging for treats. They were not only bred to hunt, but also to kill their prey; in your household, that "prey" is likely to be your dachshund's toys, and he will kill one at a time in an effective manner.