Funny, I couldn't see what to look for and I believe you are talking about what appears to the left of Scarecrow as they near the end of the lane.
If so, it looks like a Tucan beak.
Don't think it is a suicide. The film would never have been released if someone killed themselves on set.
As for the myths on the link, do you believe in coincidence. No concrete facts to back this up. In fact no even remotely dodgy facts that have been twisted are provided to at least explain why this conclusion has been reached.