Lets see if I can draft some solid rules here.
For the time being, assume the conditions for Revolution remain the same. So, at the end of a Russian turn, if the Revolution occurs, take the following steps:
1. Remove all Russian control markers. Determine control of any tts affected according to units present. If the tt is empty, then nobody controls it and the first unit to enter takes control.
2. The tts of “Great Russia”, that is Moscow, Karelia and Tartarstan, become Red tts. Place a Communist control marker in each to indicate this (borrow some USSR markers from your WWII games). The presence of units from the other Allies does not prevent Red control at this stage. Replace every unit in these tts (including the new units just placed in the capital) with Russian Red units; any WWII Russian pieces of a suitably distinct colour will do. The CPs must relinquish control of these tts, the Reds effectively become a 4th Central Power.
3. Nominate a CP player to control Communist Russia, but keep income and units separate. The Reds collect income from Greater Russia for next turn. The Reds may enter CP controlled Russian tt, but may not take control of it. However if they liberate a Russian tt from the Allies and Whites when there are no other CP units present, they may keep it.
4. Any Russian units in other tts remain in place and are still controlled by the original Russian player. These become “White” units fighting to overthrow the Communists. They function as a separate power, but are limited in ability due to a lack of cohesion; some of them are nationalists, some royalists, some republicans, some separatists.
5. The new order of play has two Russian turns:
a) White Russians. If the Allies control any original Russian tts, these are considered to be controlled by the Whites, who collect income from them at the end of their turn. Use the original Russian “Imperialist” markers to indicate White control. White units continue to contest tt with the CPs, and may defend with Allied units.
However, until Moscow is recaptured by the Allies, the Whites are limited to buying infantry units (they can keep any other pieces they still have). These can be placed in any White controlled tt at the end of their turn, but no more than one unit in any tt.
b) Reds. May place any units they buy in Moscow.
6. Although Russia is considered to be in a state of civil war, the rival Russian factions can interact with the other powers, Whites allied to the Allies, Reds to the CPs, with the following restrictions:
Red units may never move outside original Russian tt in any circumstances, even to attack Whites there.
White units may exist and fight outside Russia, but may not gain control of non-Russian tt. If a White attack gains such a tt, control must be handed to a full Ally.
7. If the Whites gain control of Moscow, they obtain the right to build any unit there, while the Reds are now restricted to infantry only placements.
8. The Civil War will probably not end before the game, and as long as it continues then the CPs are considered to have fulfilled one part of their victory conditions, even if the Whites have regained Moscow.
9. If the Whites (and the Allies) completely eliminate all Red units, then the Civil War is a White victory. Russia is fully restored as an Allied power, and the CP lose their victory objective in Russia.
10. If at any time the Reds and CPs control all original Russian tt, the Civil War is a Red victory. The Whites cease to be a faction, and neither they nor the Allies may enter Greater Russia, though they may still fight the CPs in tt annexed from Russia. White units remain on the board and can be used by the Allies to fight, but the Whites can no longer control tts or collect income. Since Reds cannot move outside Russia, there is no need for further Red turns.
Issues:
Petrograd was the centre of the Revolution, as well as the Russian fleet. Since on this board not only is it not the capital, but it seems to have been placed in “Livonia”, therefore outside Greater Russia. On a more accurate map it would be inside Red tt, even if the capital were moved to Moscow. If using the official board, then, we simply have to pretend that the city never existed.
The Russian Fleet.
Ideally the Baltic fleet would become Red, being assigned to the Petrograd/Kronstadt Naval Base. However since on the official board this base is in CP annexed Livonia, this presents a difficulty. Probably it depends on CP control of Livonia.
The Black Sea fleet, being assigned to Sevastopol, would depend on who controls that NB. However the Allied players may decide to move such ships out of the Black Sea in anticipation of this, dependent of course on being able to sail it through the Turksih straits.
In fact, the CPs should be able to keep all Russian naval units bottled up in their home SZs to become Red ships, however the same restrictions apply to the Red navy as the Red army: they may not sail outside “Home” waters, i.e SZs with a Russian NB.
Russian ships anywhere other than in Red or CP controlled NB SZs become White.