Answers to your questions:
Were most of [the super-wealthy Russians] able to flee the country?
No. Most of them were executed by the Bolsheviks along with their families and anybody that the Bolsheviks deemed to be in league with them.
You can get a sense for the survival chances by reading about the last Grand Dukes of Russia. Remember that these are the richest and most powerful of the nobles and had far more resources than most of the nobles, yet even so, many of them died. The Grand Dukes who surived:
Nicholas Nikolaevich - lived under the protection of the French
government
Michael Mikhailovich - exiled by the Tsar long before the war, all assets in England; went crazy after virtually all of his relatives were executed
Peter Nikolaevich - escaped with his wife and children; lived in retirement on the French riviera.
Alexander Mikhailovich - escaped with his wife and children; lived in retirement on the French riviera.
Cyril Vladimirovich - escaped with his wife and children; was a leader of the Russian exiles in France.
Andrei Vladimirovich - escaped and lived an upper middle class life in Paris.
Dmitri Pavlovich - exiled by the Tsar in 1916 after he conspired to murder Rasputin; was able to keep his wealth and lived among the emigre elite in Switzerland.
The other 7 grand dukes of Russia were all captured and executed along with their entire family and all their relatives.
or Otherwise avoid repercussions from the new regime?
A small number became Bolsheviks themselves and escaped destruction, but most such people remained under a shadow of suspicion for the rest of their lives. One example was David Bronstein (known as "Trotsky"). Bronstein was the son of a wealthy factory owner and he became an important Bolshevik. Eventually he had to flee the country and was assassinated in Mexico.
Were those that evaded the risk to their lives able to keep much of their wealth?
No. The ones who escaped took what they could in movable valuables, but typically this was only a tiny fraction of their wealth, which was mostly tied up in land or other non-movable assets. A few had foreign bonds, notably French bonds, and this allowed them to remain rich after fleeing, but this was only a small number of people. The large majority of the refugees escaped with nothing but the shirt on their backs.
When you read about rich Russians in exile, in most cases those were Russian nobles who were already living in Western Europe at the time of the revolution and just stayed where they were. In those cases they were able to maintain their lifestyles somewhat, but of course their income was terminated, so they only had what savings had been set aside.
Was their lifestyle impacted significantly?
Obviously.
The life of an exile is lonely. I remember when I was a student at Princeton many years ago, several times in the very early morning, just at dawn, staggering back from the parties, once or twice I saw an elderly woman walking a large Russian wolfhound on the greens of the campus. This was one of the Great Russians (Bolshoi Russky) who had escaped when she was a little girl. She walked in such a graceful and delicate way that you cannot imagine, yet with her gaze fixed ahead, oblivious, like she was drifting through another world, and I was only seeing her ghostly shadow. It is an isolation and loneliness beyond comprehension.
