Referring the list in my post above for countries possible between Dubrovnik and what we now know to be Osaka and Taipei, I have developed some specific ideas for the 2 stops that we need:
1. The #1 city that appeals to me is Shanghai. It would be just before Osaka. Beijing, the Great Wall, Xian and Shanghai have all been done in prior Amazing Races. Cruising up the Yangtze River would have no real appeal for The Amazing Race, so the next best place left in China in my opinion would be Shanghai, with an emphasis on a trip to the suburb of Suzhou.
2. I don't think there will be any stops this race in India. If there were, the top place that has not been done so far is Bangalore and another is Goa.
3. I liked southern Russia as a possibility, but flight schedules east do not fit well so they are effectively out of the running.
4. Next we have to look at two distinct cases, one with Vilnius after Dubrovnik and the other with Vilnius before it.
Vilnius Before Dubrovnik
This makes a more southern route likely. Only one stop is needed. I like the use of Istanbul as the connecting city for a daily nonstop flight to Shanghai, TK20 2320 to 1630, stopping in Beijing and crossing 5 time zones along the way. I doubt that Istanbul itself will be used again. I like Ankara the best. There are 7 nonstops a day from Ankara to Istanbul. Athens is second best. there are 3 nonstops a day (only one in the evening) from Athens to Istanbul. There are a number of other cities with nonstops to Shanghai, but except for Moscow they are all to the west of Dubrovnik. Istanbul as the connecting city involves minimal backtracking.
Vilnius After Dubrovnik
In this case, we need only to go as directly as possible from Vilnius to Shanghai. There are two possibilities on July 24, through Helsinki and through Moscow, arriving late afternoon or evening of the 25th.
Shanghai is an assumption, logical because of its geographic placement. There are any of over 100 cities that could have been selected for either of the slots available for the combined two cases. When evidence is available to indicate otherwise, alternative consequences can be examined.