The White Movement manages to form some a coalition of sort and a semi unified command (to a degree). At least, most of them agree that Alexander Kerensky is the leader and that the Soviets are the main enemy in this tl.
The "Whites" in the strict sense (the armies in the south, the northwest, and Siberia assembled from right-wing volunteers, Cossacks, and conscripts by ex-Tsarist officers and NCOs) didn't agree on a government or leader (being essentially warlords) but didn't actually fight eachother and they certainly agreed that the Soviets were the main enemy. A notional adherence to one government isn't going to help them overcome the Red control of the infrastructure necessary to keep armies in the field.
None of this is particularly relevant. The White Movement only really got going after Brest-Litovsk. In March 1918, the Volunteer Army of Southern Russia was a few warbands on the run in the Kuban.
Then they allow several countries to break free if they fight the reds
An old cliche without much basis in fact. Who, prior to March 1918, are they going to "allow to break free?" And what good would it do them anyway, even if we're talking about White victory over the Reds and not Russian victory over Germany? The Finns and the Poles have absolutely no need to take the deal, since they can make themselves independent. The Estonians and Yudenich had an uneasy co-operation going on as it was. The Georgians and Armenians had all their forces facing the Turks; the Azeris were fighting the Armenians with their minimal forces and the only target they can strike at is the north Caucasus, already controlled by the Shamilists, who were basically more anti-White than anti-Red. The Ukrainian Directorate Army was after the second loss of Kiev pretty much nothing, with the Whites in Ukraine being far stronger. And what "Whites" there were in Central Asia generally came to understandings with the Basmachi under Britain's aegis.
Basically, the only obvious thing is for Pavel Bermondt-Avalov not to waste his time in Latvia, which isn't going to save the Whites in any way, shape, or form, still less save Russia.
and the Entente send a lot more help.
The Entente could send all the guns in the world (well, it couldn't, because in March 1918 it still needed them to fight Germany, but you get the point) and there wouldn't be enough Whites to carry them. The Whites had at their core small, ideological units of hardened veterans where ex-colonels led companies and most footsoldiers had been subalterns and NCOs. Around this were masses of hastily conscripted troops with little training or morale who could be relied on to defect to whoever appeared to be winning. Once the officers regiments experience attrition against the reds, who have military industrial, a recruiting pool, and a proper system of organisation new divisions with cadres, the whole structure comes apart. That's what happened outside Moscow, and the Whites were done for.
Then to send even more manpower in Germany is allowed to pay off parts of its war debts by sending soldiers to fight in Russia. Then give the Whites a dose of luck and the Russian Republic has survived the war. Which is a better victory than complete destruction.
Well, not really, because Russia is now basically China. It's divided into warlordistic fiefs and it's going to take the strongest time to assert itself. The country is utterly knackered, foreign troops are everywhere.