A few words about the surnames. The spelling "Prankzkiewich" is a partly phonetic Polish spelling of what in Lithuanian would be "Pranskevic^ius". The Polish spelling suggests that the ancestors came from the present-day areas of southern and western Lithuanian, perhaps along the border with Poland or Belarus. The origin of this name means son of Pranc^iskus or son of Frank. There are nearly 70 listings in the online phone book for Lithuania for people with this name (including the unmarried female form "Pranskevic^iute" and the married woman's form "Pranskevic^iene." The letter "c" in Lithuanian is only pronounced two ways: like the "c" in the English word "fence" or like "ts" in "bits." The other "c" has a birdie or mark over it showing that it is pronounced "ch" as in the English word, "church".
Stratowski is also spelled as a Polish name (Lithuanian does not use the letter "w" but "v" instead) and the ending "-ski" or "-sky" is also Polish. The Lithuanian version of the name would be something like Stratauskas.
"Donatis" has a Lithuanian ending, but more likely would be spelled "Donautis" or "Donautys" or even "Danautis."
The name "Syneticus" does not appear to be Lithuanian spelling either. Today, the "-y-" would be "i" or "-ie-". The "c" would be "k" because of the rule noted above about the only forms of the letter "c". So it would be spelled in Lithuanian something like "Sienetikas" or "Sinetikas".
So it appears that the names you are searching for have been altered or are phonetic and largely Polish in form. Therefore, your search will have to take into account a number of variant spellings on various records and documents.
With only the information you have given here, you do not have enough even to begin searching. You will need to give folks on this and other such forums as much information as you have. For example, what are the given names associated with these family names? Where did they live in the U.S? Spouses names? Dates of marriage; names of children, etc.
The reason this information is needed is that with it, one can reasonably search online for census records and draft registrations for clues to the name spelling actually used by the individuals and for the dates or their arrival in the U.S. With this information, one can search immigration records and perhaps find their passenger manifests, which often give the town of birth or of last residence in Lithuania. Armed with the town or village name and the given and surname variant spellings, one can then write to the Archives in Lithuania to obtain records of birth, marriage, death, etc.
Right now it would be very difficult to search for variants on "Prank" or "Pranzkiewich" or the other names. We'd got far too many hits and wouldn't have other data to use to confirm that we'd found the "right" person.
So you appear to be at the front end or beginning of an odyssey.