My guess Russia is not going to back Assad real soon.
Hard to say. It's all about Russia's interests, which are served by being allied to the Syrian government.
The Syrian government may or may not be synonymous with Assad personally. If the two can be separated, then I could see Russia offering "asylum" to Assad in exchange for some other, Russian-backed government.
What I can't see, is Russia abandoning the Syrian military to its fate -- that serves nobody's purpose, even if the Syrian military is ultimately responsible for this attack. So Assad has to go, rather like the manager of a baseball team gets fired when his team sucks.