I've sat behind, but never in the bulkhead itself. I looked through my photos and I don't have one to refresh my memory but I think it's a standard fold over style tray. I don't recall anyone acting as if it was flimsy and it supports a standard PY/Y tray.

Light shouldn't be an issue. As soon as the CAs get up after takeoff, they move curtains across the aisle way which have somewhat of a gusset to keep them closed and block light by the lavs passageway. The door openings themselves are on the opposite wall away from the PY bulkhead. Not sure how much noise or vibration can be observed.

My favorite spot!