Effect of Life on Measured Temperature of the Universe
If life is endemic in the Universe, which it certainly is, it would affect the measured temperature of the Universe. If we measure the average temperature of a room containing a refrigerator, but do not include in the average temperature the (lower) temperature on the inside of the refrigerator, the measured average would be slightly hotter than the room really is because we are not including the cold area inside the refrigerator, but we are including the area subject to the exhaust from the refrigerator's motor and heat pump.
Similarly, we measure the temperature of the Universe and see the exterior of life, the increasing disorder, as higher temperature, without accounting for the order inside of life.
Another way to say this is that gravity is a measurement of order and that there is "hidden" order in life. There is support from Erik Verline (here, at arstechnica, here in a PDF of this article), a Dutch theoretical physicist, for the idea that gravity is a measurement of information and that this information would increase the gravitational pull of black holes. I would add to Prof. Verline's work, by noting that order "hidden" in life would increase gravitational pull wherever life is found, not just in black holes (however faint this would be, for bodies of order as small as ourselves).
This would not necessarily "fix" all of the matter/energy imbalance which we are struggling to understand, but it may account for a portion. As noted, the Universe is very large.