Best PODs to restore Poland-Lithuania

[The Forty-Eighth Rōnin]

What are the best possible PODs for a successful restoration of the Polish-Lithuanian Union, either as a monarchy or republic, after WWI?

 

[Augenis]

After 1900? Unless you prefer military unification, then none.

And even then, even if you have something like Zeligovski's Mutiny succeed in full (somehow), there is no guarantee that the resulting country will be a PLC and not a Poland with an autonomous (or not) Lithuanian region.