Sewell had been fashion director of Style.com, which Farfetch purchased in June.
The role is a new one, and Bellavita will be overseeing the digital editorial team.
Colino most recently served as digital director of Condé Nast Mexico and Latin America.
Jonathan Newhouse expressed his disappointment to colleagues about Style.com.
Style.com will discontinue operations immediately and redirect to Farfetch.com.
Industry looks for Enninful to bring diversity and strong fashion imagery to the pages of British Vogue.
The company has named Wolfgang Blau and Albert Read as president of Condé Nast International and managing director of Condé Nast Britain, respectively.
Albert Read is in the running to take over one of Nicholas Coleridge’s posts.
His two successors will be named on Jan. 16.