i watched Transylvania be formed and then grow beyond Hungary's borders in my Ethiopia game where my only influence in the area was destroying the Ottomans, but well after they had already formed and grew a bit.
Hah, in my current Najd game Transylvania did the very same thing, though I haven't killed off Ottomans. Fun times.
As for rare tags... This current game is the first time I ever saw Doughlat and Khalkha, and both rather strong.