It's tricky-DB and others are within her circle of friends. DB is not a minor so he can be discussed I think within the context of the conversation. HS and TS appear to be at a minimum material witnesses, although HS was a minor when she disappeared-is he a minor now?? TS also went to the media with multiple statements regarding the story, so she is certainly fair to discuss. HS is the last seen...or TS is the last seen because she went on TV and made a statement regarding the last time she physically saw Cassie. TS indicated that her son received a text from Cassie and TS related the story regarding HS dropping her off. It is her assumption that this happened unless she was actually there. IIRC, BR/JC claim to have heard Cassie, and did not actually see her.
So HS, TS and others have not been ruled out as suspects themselves, but they havent been named in the media so sleuthing them would have to be within a specific context I think....clear as mud??