The latest OSX's do have a setting by which a number of programs keep running. It's called "Turn on Power Nap' (in systemprefs-->Energy) and mentioned are mail, agenda, iCloud updates. Maybe there lies a solution.
I also do know there are small apps that (when installed) will enable a MacBook to keep running even with the lid closed. This is mainly used by people who want to watch a movie on they TV/Mediaplayer and that originates on the MacBook. Enclosed a smaal list with apps that are supposed to do that.
if you want I can test DVBlink with these apps.

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