Here is the revised haibun with my suggested edits incorporated:
Into the Sea
Where do you sleep? In an abandoned steeple.
A night light? I don't blow out my candles before sleep.
What dreams? A gray ghost whispers, "Mirrors always lie."
stone Buddha—
in his lap, the glint
of mica
The sky.
I've kept the line breaks to maintain the spacing between the questions/answers for flow and rhythm. Changed "whispered" to the present tense "whispers" as you suggested. Let me know if you have any other thoughts or would like me to clarify/explain any of the edits! Overall I think