Double last names? - Zabawa, Czermak, & Zabawa Czermak?

So I was building up my genealogy, bit by bit, and recently looked into my paternal Grandpa's mother's family. Thank heaven for newspapers, LOL! I was able to find her six siblings, mother, and short mention of her father Joseph. Find a grave helped me further to find her mother's grave with her father's name as well:

DROGI MAŻ I OJCIEC
JOZEF F.

Here is my new conundrum. My great-great grandmother's name is Mary Zabawa Czermak, naturally her husband's name is Josef F. Czermak. Using familysearch.com next, I found immigration record of Jozef, but with a second person's name: "Jan Zabawa",described as "uncle" (seems from jis mother's side) The Jozef I'm looking at was 15 at the time, by the way.

So would my great-great-grandmother have received Zabawa as a middle or last name in addition to Czermak by marrying my great-great-grandfather? Or is this a matter of coincidence that her middle name is the same as Jan's last name, regardless whether related, marriage or otherwise?

Wow, that is a good riddle wrapped in a mystery. Zabawa isn`t such a popular surname, so it is probably not a coincidence. However, the family relations provided by your source might contain errors.

@pawian
🤷🏻‍♂️ maybe my source is wrong, but it does provides photocopy scans of the original immigration record, but then again that might be explained by human error. But it is not common for women marrying to adopt multiple last names? My Filipino wife, for example, both keeps her last name and adopts my last name. No chance that the Mary in question couldn't have adopted last names from both sides of Jozef's family?

Which isn`t such a perfect source, either. Those clerks who put down immigrants` names were only humans.

Marianna Czermak was my grandmother. Her maiden name was Zabawa. Josef was my grandfather.
I have researched both families back to Poland and have connected with many relatives. If interested, please contact me, I have a lot of info to share.

Jan was Marianna's older brother who came to America first.

Czermak as in a certain erstwhile Mayor Anton Czermak of Chicago, was the unintended victim of the attempted assassínation of FDR in around '38.

@BCz
Perhaps you find their tombstones to verify?
Or any other clues for me to match?
I think I misread also, Jan was the brother-in-law of Joseph I think.

@OdrowazP
Please contact me...I'm in NJ. b.czermak@outlook.com
I'm sure I can answer all your questions,
Look forward to hearing from you

@OdrowazP
Scratch that, Jan is the uncle of Jozef,
Brother-in-law of his father Wojciech.

@OdrowazP
I have copies of Birth records for both Josef and Marianna. More than willing to share.
All digital...Czermak and Zabawa family histories back to the 1700's.
Just let me know if you would like to have them.
I am son of Leo the youngest brother of your great-great grandmother.
I assume your grandfather is Walter, my first cousin.
I have been to Poland three times and have connected with many, many families in the Zabawa family lineage.