A theatre-esque mode may be implemented in the future. VOD chat, however, would use undocumented and unstable APIs that could change, breaking the implementation at any time. If implemented, it will likely happen after the Twitch Helix API is stable.
For anyone looking for a similar Android solution, found this through a post about Twitched in /r/roku:
https://play.google.com/store/apps/details?id=com.instantbits.cast.webvideo
Worked for me.