Is it obligatory for a woman to observe Hijab in front of her husband's maternal uncle and paternal uncle? And does the phrase "fathers of their husbands" in the verse of Hijab include the husband's father, grandfather, paternal uncle, and maternal uncle?

The husband's paternal uncle, maternal uncle, or brother are not considered mahrams, and the wife must observe hijab in front of them. Mahrams are fathers and grandfathers (no matter how high in ascent), and the husband's sons, grandsons, and granddaughters (no matter how low in descent).