Megan
Can you provide the documents you spoke about for me to take a look at? Hopefully you will before Friday morning as I'm going away and be back on 20th.
Pretty sure you know that one starts from oneself going backwards generation thru generation collecting record on each ancestor. In those US records a descendant should be able to find ancestor's place of birth in "old country". Trust but verify. Don't just assume just because it shows up somewhere that he/she is your ancestor. At least 3 documents on each ancestor.
All the documents have to line up.
Go back to the church your GADELIS ancestor was married and their children baptized. How soon after arriving to America did Marta [Martha] [someone read the Mariha wrong] and Joseph marry? I would think they were "birds of a same feather". Common language and common tradition to observe. How would a Croatian [but your query is on Serbia's board] communicate with a Lithuanian if they did not have English as a common language.
Zlatica