Weepers do count for detection. They do raise the Chaos level if they are killed. Kills by Rewired traps will contribute to your kill amounts and Chaos; that's Watchtowers, Arc Pylons, and Wall of Lights. Rats, Hagfish and River Krust do not raise Chaos if killed.

What counts as killing in Dishonored?

In Dishonored 2, a character killed whilst in a chokehold counts as a kill. ... Not to mention that if someone dies of an accident whilst linked to another person with Domino, that other person's death is counted as a kill.

Why do weepers attack you?

However, it is believed by some that weepers are not actually hostile, and their "attacks" are really attempts to seek aid from uninfected humans. The Heart reveals that at least some of them have chosen to spend their last moments infecting any sane person they encounter.