Do you think Turalyon participated in the Tyr's Hand peasant massacre?

[Zmagoslav]

perhaps; but surely they're made up of the said knights who took part in the quelling of the uprising

Not according to the "official strategy guide".
Some of those knights were trained into paladins afterhand, but weren't really paladins at the time of the "massacre" (heck, the guide even suggests the knights were trained after the quelling).

[Aurabolt]

perhaps that's the reason why he didn't want to purge Stratholme, like he has seen enough

I never said he didn't know about it. Participated? Unlikely.