The Universe is missing mass only in the context of the theory of the Big Bang. In trying to work out the equations to make the observations fit the theory, contradictions keep arising. The "missing mass" is (as was epicycles in the days of the geocentric theory of the universe) is an invention of what "must be there somewhere" to make the observations fit with the theologically desired outcome.
Number 3 actually ties into this because the entire theory of the Big Bang rests on the ASSUMPTION that there is no other explanation than relative velocity to explain that spectra from more distant objects is shifted to the red (a conclusion Hubble himself did not make). If light red-shifts because of some other phenomenon (which is supported by the fact that the observed red shift in the sky is quantized) then the prime evidence for the Big Bang collapses.
Oh yes, as for number 2, the changes in the paths of Pioneer are easily explained if you abandon the ASSUMPTION that the Oort cloud is uniform and symmetrical.
As for number 6, I have a personal interest in this one since I was part of the Viking missions. And yes, we concluded we found like on Mars, but as this article reports, NASA over-ruled us. The greatest political pressure to deny life on Mars came from religious groups.