The Death of the Chieftain and Bolshevik Planning and Help Thread

So, while I still intend on finishing my timeline Dead By Dawn, and have several other projects Im currently working on a TL called "The Death of the Chieftain and Bolshevik". As I am still doing research, I have some base points I've decided on. So far, I want to have the 1934 Revolution in Spain result in an early Civil War that will lead to a surviving Spanish Republic, possibly led by Eduardo López Ochoa (if the right POD can be found, as he was apparently a left leaning officer). For Ochoa I was thinking when he was sent to squash the unrest in Asturias, to go over to the rebels, but I don't have the perfect POD as of yet.

Another major component of the timeline, is for Hitler and Stalin to be dead by New Years Day 1941. For Hitler, Im going to have him assassinated by Beppo Romer in late 1934, but once again I lack the POD to allow this plot to succeed. With Hitler dead, I envision a struggle between Himmler and Goering. Goering has the legitimacy, but since Himmler and Heydrich helped plan the Night of Long Knives, I think the SS would react swiftly following the realization of Hitlers death.

What Im really puzzled on, is the death of Joseph Stalin. As far as I can tell from some casual research, there are no plots against Stalin's life that are well known. Operation Long Jump is mentioned, but as that occurs in 1943, far beyond the initial POD period, I won't be using it. I've been thinking of some kind of car accident, but that might be a little lazy.

So yeah, if you have any ideas that could help me, just drop a comment. Thanks in advance.