Hi Katherine,
Again, please keep in mind I have not studied extensively this tragedy of the Dalits. However, having some familiarity with Gandhi's life, I do feel very sure he did strongly support equality for the Dalits.
From one of your links: "Gandhi called the outcastes Harijans - the children of God - and wanted to accommodate them within the fourth varna."
Gandhi's mistake was that he supported equality TOO strongly, and was unwilling to compromise. He wanted all of India to fully change their hearts, and wipe out the whole concept of untouchability. And, he felt this could not happen if the Dalits were segregated into voting for their own representatives...he felt this would just continue the separation. Thus he fasted almost unto death; however history has shown he was wrong here, I feel. You do need to make realistic compromises.
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Incidentally, I also read in your links that Ambedkar wanted to abolish the caste system altogether...and that is indeed in harmony with the ancient teachings. The actual wisdom from ancient seers is that we are all born with certain inclinations, tendencies, which fall into four overall groupings. But never were those four groupings intended to be formally established as a social caste system, because we are all individuals who need to find our own way; not born into a rigid caste from which you cannot escape.