At least those different spellings of surnames in your family all sound the same, so they're easily explained. In my family I have great-uncles surnamed Charney and Chernoff and earlier transliterations in the JewishGen records are even more varied.
You don't mention how and when your father-in-law's family arrived in the U.S., but because of the different spellings, my guess is that each one with a different spelling arrived separately. Living in Latvia, they primarily spoke Yiddish and Russian, the first written in the Hebrew alphabet and the second in the Cyrillic alphabet. When they gave their names to the steamship company's agent when purchasing tickets or to the company's officer when being listed on the shippping company's manifest before boarding the ship, that person wrote down his best guess at how the name should be written in the alphabet we use. That was the first time anyone would have written the name in this alphabet. Since there were no definitive rules about how to represent a sound from a different alphabet in English, a little variation by different ship's agents or employees is not unusual.
When they came to the U.S., the brothers probably continued to use whatever spelling was on their ticket.
It's also possible that they arrived at the same time with the same spelling but due to a cultural history of not caring much about surnames plus lack of familiarity with English and its alphabet, the brothers wrote the name differently after arrival. My grandfather used the spellings Wolf, Woolf, and Wolfe on different U.S. census reports. It didn't matter. Spellings of names after arrival in the U.S. often didn't become consistent year after year until the person filed a petition for naturalization or signed some other official document such as a draft registration card.
Judith Singer
researching CHARNEY and variations in Lithuania, SORTMAN and variations in Lithuania
