Thank you very much for your help.
This week I'll try to get their birth certificates at local church, so that I'll provid the exact information.Slovenia at that time was under Austria.
Franc (american Frank) was married with Lenka, Ivan did not get married.Franc was a tailor in US, I'll try to find out where he learnt that profession.
Also I'll provide an American pronounciation of last name.
But when the Vucajnk family sent packages to former Yugoslavia they always wrote Vucajnk in address, well that address was lost.