Haunted Houses

quiet, inoffensive ghosts

The phrase directly describes the ghosts as quiet and inoffensive, which means they are not threatening.

The forms and sounds that the speaker perceives

The stranger can perceive only what physically is, while the speaker can see and hear the dead as well.

True

The poem begins with the idea that such houses are haunted because the dead remain present in memory and feeling.

harmless phantoms, quiet, inoffensive ghosts

The poem describes the dead as harmless, quiet, and inoffensive. It clearly rejects the idea of dangerous or mischievous spirits.