This question contains spoilers…
(view spoiler)[So, was Yelena actually raped? I'm pretty sure she was, but I'm just a bit confused since closer to the beginning of the novel she stated that Brazell/Reyad "never crossed that line"? I couldn't find the page after searching and searching, but I know it was mentioned somewhere around the time that Yelena was thinking back to how she use to be an acrobat and how Reyad caught her practicing and had forced her to perform (hide spoiler)]
Alyssa Comeau She was raped. When she said he "never crossed that line" she meant that while Reyad and Brazell were both trying to train her, Reyad held himself back and only went so far due to what is father would approve of. But when Brazell finally gave up on her, Reyad took that as his opportunity to do whatever he wanted because he knew Brazell wouldn't care anymore, and that was when he raped her like he had always wanted to.
Amy Kaufman She definitely was raped by Reyad (according to the passage you mentioned). I think her "never crossed that line" distinction was that together, they never crossed that line (when she was being trained by them both). Once Brazell decided he had no use for Yelena and gave her to Reyad, she was definitely raped.