Hi,
Just a few legal points here. First, It is pointless to apply any pre-1918 law in this case. The Imperial Family was, under existing law, fully immune from criminal prosecution for any act unless so ordered by the Tsar, and that continued after 1905. The Kerensky government never enacted any legislation to actually countermand that. I suggest, for an even playing field, and since this is a "modern" intellectual exercise, we use the Canadian "Crimes Against Humanity Act", which is the current standard in International Law.
Second. There is NO statute of Limitations for Murder or Crimes Against Humanity, and for the sake of the discussion here, I suggest we waive the defense of Statute of Limitations for any other criminal offenses you might consider. (it just makes the discussion more interesting)
to get you started:
"crrime against humanity" means murder, extermination, enslavement, deportation, imprisonment, torture, sexual violence, persecution or any other inhumane act or omission that is committed against any civilian population or any identifiable group and that, at the time and in the place of its commission, constitutes a crime against humanity according to customary international law or conventional international law or by virtue of its being criminal according to the general principles of law recognized by the community of nations, whether or not it constitutes a contravention of the law in force at the time and in the place of its commission.
more here:
http://laws.justice.gc.ca/en/C-45.9/41179.html#rid-41233