As far as Q,s 1 and 2 go:
1. I just created an 'os:execute' event to launch "C:\Program Files\DNTV Live!\DNTVLive.exe"
2. Then created a button to link to that event. This can be done in the skin editor for any skin you wish).
No plugins...
Then I created 'plugin:xSendKey' events for 'channel up', 'channel down', 'record' and 'stop' (CTRL:U, CTRL:D, CTRL:R and CTRL:S respectively). These, I then mapped with the xremote plugin to my remote keys. When pressed the simulated keystroke combinations are sent to the application in focus (in this case DNTVLive!). Hope this helps.