I am aware that thousands of Poles fought on both sides of the war, in the hopes that their countries would reward their sacrifices with independence and that Germany and Austria-Hungary tried to set up a puppet Polish monarchy in 1916, but did anyone, in either the Allies or the Central Powers, really give two seconds thought about Polish independence? Had the Allies won the war with Russia still in the war, would they have encouraged Russia to give Poland it's independence or would they have been perfectly willing to allow Russia to keep Poland as part of their territory?
Well, Polish territory was divided between 3 countries that participated in the War, so definitely at least these countries would "care" about Polish independence. Wilson's fourteen points also specifically highlight the need for an independent Polish State (point 13). That symbolizes the US understanding of the usefulness of Poland, especially in the face of the Russian Revolution. Since all the other countries in the Entente agreed with this specific point, one could say that the matter was unanimous.
As for your last question, it is more in the realm of Alternative History, but I can tell you that the Polish nationalist movement was fractured and not necessarily unanimously behind the idea of immediate independence. In fact, one of the two main actors of this movement, the National Democratic Party of Roman Dmowski, seeked at first the unification of Polish borders and a greater degree of autonomy, but still under the framework of the Russian Empire. For that reason his party received support from the Imperial Russian government and he became some sort of official representative of the Polish people within the Entente. His ideas about independence only changed when Dmowski realized that Russia would likely lose the war.