Three tones, three flavors of the same mouth-crowd glyph: hǒng (sweet-talk one person), hōng (roar of a crowd, noise-painting), hòng (rowdy disturbance, brawling-style heckling). Test by context:
哄宝宝 (coax the baby — gentle one-on-one = hǒng);
哄堂大笑 (whole room laughs — mass noise = hōng);
起哄 (heckle / make a scene — rowdy disturbance = hòng).