Socialist parties will be much more successful in the West (there's no Zinoviev letter to sabotage the first Labour government, for instance, and I would think socialism isn't delegitimised in the United States).
Probably, provided that the victorious whites don't seek to demonize all socialist/left wing element to excuse their very likely crack-down and repression. [While better than OTL Russia it would still be very repressive I suspect].
A restored Tsarist Russia is going to be a major threat to peace, perhaps trying to deal with its internal strife and economic troubles by expanding into Eastern Europe in the late-1930s.
I don't know. It's going to be weak enough due to uncertain control that it's unlikely to pose a major threat or be able to industrialise as rapidly as a democratic or even a communist Russia.
The other big bonus is that while it will probably be mistrusted, especially if deeply repressive, it will not be as much a pariah as OTL USSR. Hence there will be a relatively stable power east of Germany that will act as a counter to a German military revival. This will:
a) Reassure France, which won't need to be as fixated on the need to keep Germany weak.
b) Deny the Nazis [or similar groups] the target of a Soviet threat to the east.
c) There is a Russian state that has a vested interest to block a powerful German military state, especially one with a rabid racial hated of Slavs.
Hence there is a much greater chance of avoiding a 2nd great war.
Steve