A tricky problem!
Well, as long as we talk about Napoleon and Poland it's worth remembering that he nevar was actually touched with the Independace ideas and dreams of Great Poland (from seabank to seabank). And even more he always traded them away when a need rase. In 1807 the Dutchy was created as a means to create persisten chaos in the Eastern europe with rebel sentiments etc. going on for ever and ever. The setting allowed to damage all the three powers in the region (Austria, Prussia and Russia) during the peace time. In wartime with all the three united and acting together Poland couldn't be defended and even fought at (recall 1813). Hence "No Poland" scenario is possible only if there is no peace in 1807. But if there is no peace Russia and Prussia would be allied against France and it's german allies. In this situation it would be plausible for Napoleon to try to break Saxony off the allience with Prussia AND to keep Austria out of the war. A point of importance then would be Silesia. Austria fought with Prussia for it's posession several times in XVIII century. So a promise of Silesia for neutrality or little assistance is at least probable. On the other hand Silesia could be offered to Saxony, which would increase its teritory, strength and authority enormously. Kind of Saxony was happy to the Napoleons ally for much more humble compensation - the Ducthy. So the outline is briefly as follows. In 101806 Prussian army escapes disaster in Saxony. It unites with Russian army somewhere around Berlin. Campaign stops for winter. Napoleon Offers Silesia to both Austria and Saxony in return for neutrality or participation on his side. Polish question is not raised.
Since it's fiction one more assumption is made - Suvorov survived after the Swiss campaign. By 1807 he recovered from severe illness. So a campaign of 1807 ends in Paris and Boney concludes his life polishing bars of cage standing on the Red Square in Moscow. Guarded by four drunk bears.
