I don't think they coveted Livland. At last they showed no desire to fight for. AFAIK the Senate rejected the offer to join alliance against Sweden.
Pomerania and the other German holdings will put Sweden in conflict with Prussia sooner or later (as happened several times historically). If Norway can be acquired early enough and be incorporated as a part of the nation rather than a personal union partner, things can be different.
Trading Norway for the German holdings in a victorious 1660 peace could perhaps be an option, then Denmark gets the German headache.
Is there a easy POD in the 16~1700's for Sweden to take Karilia and the Kola Peninsula.A simpler smaller way is to avoid the war against Russia, retain Finland (a far better long-term option than Norway), retain Swedish Pomerania etc and be in the 19th century in a position to affect various developments
For a post-1800 world, perhaps a little bit, but before 1808, no-one waged war north of Lake Ladoga.
As for the Oldenburgs ending up on top in northern Germany, I think it is unlikely to happen. In the 1660-1720 timeframe, they will most likely focus north, try to regain Scania etc, as they did historically. After that, Prussia, Hannover and Saxony are better candidates, IMHO.
With Scania in Swedish hands, there's no Sound Toll - Denmark has lost its richest and most populous provinces as well as the toll. .
Bremen, Werden and Pommerania always costed more than they yielded to the Swedish crown - and that is not even counting garrisons, war, etc, since they were thoroughly burned and pillaged several times during the 30 years war. They'll be a similar drain on the Danish coffers.
They wanted not just coastal access but a port. Kurland had little value for them since they couldn't use its ports in decent way before railways.The Russians will be wanting coastal access. The best option would perhaps be for them to go after Kurland, that would keep Poland and Russia, probably with the Ottomans as a triangular drama partner, at each others' throats for some time.
I think this is key point. Sweden wasted power to fight people, that didn't want to fight Sweden and let Russians to rebuild. Without August as the king of the Commonwealth, in such war they had good chance to win.Even if the Poles did not attack, August's Saxonians did, and Russian armies also operated in Poland. Polish partisans were a constant nuisance to the plundering and pillaging Swedes - and a peace was signed with Stanislaw after he was elected King and Grand Duke - Sweden considered itself at war with Poland, even if Poland did not consider itself at war with Sweden.
Maybe, but in that case the Commonwealth had more chances to overcome such problems.Europe at the time was very much you have a centralised state - your own, or someone elses, and Poland had started to weight towards the latter. Even without August and the devastation of the Great Nordic War, Poland will have problems with land-hungry neighbours.