So...how about Poland-Lithuania remaining a dominant power on the European continent?
Poland-Lithuiania does not have many chances. However, if Hapsburgs managed to keep their Austro-Hungarian empire for so long, some truly capable dynasty can do the trick with Commonwealth. Then again, if you ask me, I would say that separate Poland and Grand Duchy of Lithuania (transformed into Kingdom at some point) have more chances of success. Religious divide would always haunt PLC.
Or Kievan Rus hanging onto power, and having Ukraine dominate Russia instead of the other way around?
Decline of Kiev (and neighbouring principalities) had been caused by decline of trade with Constantinople, so it wouldn't be easy to have Kiev dominating NE principalities. However, if you butterfly Mongols away you can have several strong Eastern Slavic states competing for dominance in region. I can see Ruthenia (present-day Ukraine), Slovenia (Novgorod Republic, as they called themselves "Slovenes") and Vladimir (modern-day Central Russia). Would it be Slovenia or Vladimir who will get Siberia in this universe remains to be seen.
I noticed the Teutonic order here alot, what would it take for them to still be live and kicking?
They were sorta "alive and kicking" until late 1800s (rise of Latvian/Estonian ethnic nationalism). Before that, it was territory governed by Germans (neither Swedes nor Russians made serious attempt to assimilate Germans there) and every rich or educated Latvian or Estonian tried his best to be considered German ("Estonians" were forbidden from entering Reval until 18th century). Medieval Germans actually opposed Germanization of "natives", as it had been seen as undermining "status quo" (Germans as personally free landowners/merchants/tradesmen vs. "natives" as serfs, bound to manors).