After Sam leaps, in the teaser for the next episode, he is immediately wearing a mustache. But in the next cut, he is no longer in a mustache. It is explained in the extended opening in the next episode - the mustache gets ripped off and needs to be replaced by the make up artist.
When Sam leaps into a host, he still retains his abilities (as was proved when he leaped in place of a blind man, while still retaining his perfect eye sight). Leonard needs glasses to see, therefore, when Sam leaped in his place, he should have problems seeing with glasses since his eye sight is perfect, but he never shows signs.
The judge mentions Twelve Oaks parish. This parish does not actually exist in Louisiana, and as Louisiana is the only state in the US without counties, would not be available in any other state.