So with #3 Is this why the 5.1 channels are not passed through on the roku 2?
Why would dynamic content preclude range requests? The HTTP specification defines how to request range requests for content with a dynamic endpoint (Range: bytes=10-). In fact, iOS makes range requests (sample request headers below from an iPhone) so it is definitely possible (and advisable, IMO).
GET /testvideo/main.m3u8 HTTP/1.1
User-Agent: AppleCoreMedia/220.127.116.11A405 (iPhone; U; CPU OS 5_0_1 like Mac OS X; en_us)