Glad to hear it is working, the delay will be due to Mezzmo waiting for enough of the file to be transcoded so that it can be streamed without interruption or stuttering.

The play to VLC is odd, VLC must be registering as a UPnP renderer on your PC and then when it receives the URL it is launching Firefox or possibly there is an extension in Firefox doing this? Mezzmo is just sending a URL and a play command to the media renderer registering itself as VLC.

If it is working then we shouldn't need the logs, we are looking at jbinkley60's logs to see why transcoding is failing.