Yes, Rogerc. You described the situation well (in short). You forgot to mention that before the seizure of Kolchak's power, there were still several anti-Bolshevik governments in Siberia (KOMUCH, Siberian government, Ufa Directory).
Pro-Bolshevik forces were also not homogeneous. In Siberia, for example, the proletariat, the main support of the Bolsheviks, was scarce. And the considerable forces opposed to the Whites, especially at the initial stage, formed the formations of Left Socialist-Revolutionaries and Anarchists (the forces of anarchists were even more significant than those of the famous "Father Makhno" - but unlike the latter, they did not enter into serious conflicts with the Bolsheviks up to the end of the Civil War).