Thanks for the answer.
I stopped getting drops after Pelagie and Kalina from Edwarda, leading me to believe there was some sort of dropped girl limit (unless we get them from epic pachinko), and was thinking of giving up and moving to battles instead. (Used to be in the top 100 in battles, but dropped down to almost 6000 because I stopped battling and focused only on trolls.)
Now I guess I'll keep fighting the trolls, until RNGesus decides to get back on my side.