my opinion totally, but Id say take the train to either Biarritz or San Sebastian from Paris (theyre right next to eachother so you could do both), then hit Barcelona and Granada.  Budapest, Prague and all those places are super fun too so youre gold either way but Spain was my favorite place of all so thats my suggestion and it works out nice and linearly in terms of geography

 
I’d suggest spending the entire 11 days in Prague, you can daytrip salzburg/budapest from Prague but there’s plenty to do in just 11 days

Either option sounds pretty good, but if you choose the Eastern Europe one I’d cut out a plce or two and stay longer in some places.

Both are great options, but I’d do Eastern Europe.  I agree with Austing that you’ve got at least 1 too many cities for 11 days.  Train rides between them are going to take up a fair amount of time — but since any flight takes about 5 hours (to/from airports, check-in, security) and most flights are in the middle of the day, you lose the better part of a day if you fly. You can visit either Bratislava or Vienna as a day trip from the other, but I’d still look at cutting either Krakow or Budapest.