I am tempted to guess that it is the Nowosiolka near Podhajce. I have also found records for a Jakob Koszlak, Hrynko Koszlak, and what seems to be Hawrylo's wife Katarzyna Kozslak and possibly two daughters Paulina and Maria. Some of these records mention Podhajce.
After speaking with Zlatica, I mentioned I had pictures of the headstones of Danielo Koszlak and his wife Any - they had distinct Byzantine/Greek Orthodox crosses on them.
I did not know that Koshlak meant otter (hey, otters are cute!), and wouldn't have even known where to begin guessing, thank you!
The only other surname I have is Benzig/Benzik/Bendziuk which is Danielo's wife Any's maiden name. Supposedly she is also from Ternopil. I don't know if they were married prior to coming to Canada, or if she was born here, or what. I did find a couple, Aftanaz (Tanas) and Palagia (Polly) Benzik, who immigrated to Canada in 1900 from a "Nowosiolka" and lived in the general vicinity of the Koszlaks here in Canada, who could feasibly be Any's parents. Aftanaz was born 19 Jul 1875 and Palagia 20 Aug 1877 according to Canadian censuses.
The Canadian province of Manitoba, particularily the small community the Koszlak/Benziks are from, had a large Ukrainian population. It looks like several families from Nowosiolka lived there...