Cesar has done a couple of episodes about a dog walking on floors. One was the Dane mentioned. Another was a Lab that didn't like the hardwood floors. They too had area rugs to allow the dog to go from room to room. Cesar managed to get both dogs walking on the floors normally by walking them on a leash, making them face the fears. Once the dogs realize that they are still alive, and the floors haven't eaten them yet, they go normally. If you can remain calm, but assertive, you can get him walking normally, without fear :)
Regarding the squatting, and dancing after pooping...that's totally normal if you're a dog! If the dog has been neutered prior to reaching puberty, mos often they do not learn to lift the let, and they just squat. My intact male will often squat as well, though he will lift the leg on occasion. (He doesn't have any sexual desires of any sort, and does not react to females in heat, does not mark his territory etc. He's got some health issues, and cannot survive a general anesthetic - hence the not neutering. This may also be why he does not act like a typical male...likely has low hormone counts). The dancing after pooping...that's still a ritual, and has been with every dog I've ever owned ;)