I didn't realize you were still here. (I'm usually not either.)
I doubt very much that Tsar Nicholas II or his government in 1914 knew about the connections between Gavrilo Princip, the Black Hand, and the Serbian government.
What I don't know is whether Kaiser Wilhelm II personally authorized the deal with Lenin. I get the impression that he was not really in control of much by 1918. Certainly Bl. Emperor Karl was horrified when he learned of the plan. But of course no one on either side was listening to him...
Russia started to lose its lofty principles when the Russian ambassador was permitted to stand at a playing of la Marseillaise. I am fairly certain that this was in the very late nineteenth century.
After that, it's a small step to supporting Serbian regicides.
But history plays tricks. So the French monarchy was bankrupted by its support for the American rebels, only to be toppled later by its own rebels, with the ungrateful Yankees cheering on the executioners of their former beneficiary.
Sort of like the Americans supporting the mujahadeen against the Russians in Afganistan, only to have them turn on us.