re #1, "Instigation to racial hatred" sounds quite odd to me, though I see that it is found in relation to Italian criminal law. I can't help but wonder if the Italian verb "instigare" might have something to do with this, but haven't looked into it.
I am not familiar with the expression "instigate to something" at all, just "instigate something" (thus "instigation of" rather than "instigation to"). Of the many book hits generated by a search for that phrase (with "to") at google books, of the first 40, which were all I looked at, exactly 1 was used in a sentence, or rather, in what appears to be a word for word gloss of a religious text, the others were all in dictionary or dictionary like lists (to instigate, to stir up, to stimulate...)
In legal language, ahem, outside of the Italian context, one would normally speak of "incitement to racial hatred".
In everyday speech, one would, I think, be far more likely to say provoke, stir up, or foment racial hatred.
This is not to say that instigation would work as a translation for Anstachelung in some other contexts, however.