What do W. E. B. Du Bois, Simone de Beauvoir, Patricia Hill Collins, Michael Omi, Howard Winant, and Dorothy E. Smith all have in common? And how are they different?

All of these people are prominent intellectuals who have done important work in sociology. All of them have been particularly concerned with how society tries to define and circumscribe the lives of oppressed groups of people (that is, black women, black men, and white women), and they all offer ideas on how to overcome the oppression of being denied the social right to define oneself for oneself.
Du Bois explained the problem within the context of "double consciousness," an expression that he invented to describe the particular problem Black Americans face in being both American and black, both integral to and marginalized by American culture. For Du Bois, the solutions to oppression lay in economic and political enfranchisement as well as intellectual achievement. However, Du Bois could not quite resist elitism in regard to the latter. He envisioned that it would be a "Talented Tenth"—a select group of talented, middle-class black people—who would use their resources to help others to advance.
In The Second Sex, Simone de Beauvoir provided the first thorough examination of how society conditions women into a particular mode of femininity designed to make them complicit in their own oppression. She re-appropriates the philosophical concept of immanence, which describes a character that is both inherent and divinely mandated, to describe how women are fixed into a particular mode of being, while men are granted the privilege of transcendence, which allows them to evolve. As an existentialist, Beauvoir believed that women have a responsibility and a right to determine their own existences.
The others whom you mention, all of whom are currently living professors, deal with identity formation. Omi and Winant created the sociological theory of racial formation to help us understand how race is socially constructed and used as a tool to determine other forms of status, such as one's economic or social value. Dorothy Smith, too, looks at social organization, in particular how it impacts women. Finally, Patricia Hill Collins is specifically concerned with conditions for black women and the development of a black female point of view and response to the specific conditions of their lives. Thus, one could argue that the ideas of Du Bois and Beauvoir around race and gender, respectively, have provided these contemporary thinkers with a philosophical framework.