Having established that when shape shifters change, they all take off their clothes, since clothes don't shape shift, after Sam turns into a human from being an owl, he has a pair of jeans on. Having said that he can't really run around in the nuddy when he is rescuing a young girl.
When Eric is invited into the house by his friend, Tara has already stepped inside - she actually heard the words when she was at least one step in the house.