DLNA in this context is simply being able to stream compressed data from N9 to DMP (i.e. TV set). It does not matter what resolution of the video file is there as all N9 would do in such case is only give out the stream, no decoding is happening on N9 side. Think about it as if N9 was a small http server and your TV was a "browser".
Regarding HDMI/MHL -- there is none and will not be. Sorry, too late.