Talk:List of Equestria Girls characters/@comment-188360-20140808200558/@comment-5837525-20140808201759

Early posts identified them specifically:

http://www.equestriadaily.com/2014/05/two-new-rainbow-rocks-characters.html

http://www.mlpmerch.com/2014/05/sonata-dusk-and-aria-blaze-rainbow.html

And Hasbro's official website supports it:

http://www.hasbro.com/equestria-girls/en_US/girls/aria-blaze.cfm

http://www.hasbro.com/equestria-girls/en_US/girls/sonata-dusk.cfm