Suspect you would have a difficult time defining "external energy source" in a way that excludes fire but includes mitochondria.
True; what is meant is a simple external energy source such as radiation or a simple chemical source of energy. It's true that this is a somewhat fuzzy line though.
Which equilibrium? Stars are far from the eventual equilibrium of the heat death, and also not at equilibrium with the surrounding vacuum.
I specifically said far-from-equilibrium chemical species and reactions. The chemistry that goes on inside a star is very much in equilibrium conditions.
Not clear whether viruses, prions, and crystals are included or excluded.
Viruses are not self-sustaining systems, so they are obviously excluded. You have to consider the system of virus+host (plus any other supporting processes). Same with prions. Crystals are excluded since they do not have any non-equilibrium chemistry.
what is meant is a simple external energy source such as radiation or a simple chemical source of energy.
I do not see how this answers the objection. All you did was add the qualification 'simple' to the existing 'external'. Is this meant to exclude fire, or include it? If the former, how does it do so? Presumably plant matter is a sufficiently "simple" source of energy, since otherwise you would exclude human digestion; plant matter also burns.
The chemistry that goes on inside a star is very much in equilibrium conditions.
Again, which eq...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.