Agree both my son and now my dd who is 2.5 too, have gone through a scared of the dark stage so for both of them i introduced a night light. It a plug in one, that stays on all night. Doesnt wake then up at all.
Also my ds prefferd the door open we would tell him that the hall light would be on until he fell asleep but this would not be on in the night. He was fine with this. DD has followed suit and recently asked for the door slightly open (about an inch) but they have their night lights on all night.
Think their imagination goes haywire at this age! Shadows and noises!!