Name change record via Green Card application - FOIA request question

Has anyone successfully gotten a hold of an old US Green Card application record via a FOIA USCIS request to prove name change? Or in general dealt with TECO on a complicated name matching situation?

My mom is now going through the process of reclaiming her lost TW passport after over 50 years. We brought her Household Registration Transcript, but the problem now is her US passport name doesn't perfectly match what TECO has on record. It is extremely silly because the romanization on TECO's record isn't even correct! Her last name is 張, her US passport has the correct romanization "Chang" but for some reason TECO has it as "Chan." 🙄

We are now going through the process of reconciling the English name on file. She got a green card through marriage back in the 1970s and assumed her married last name right away (not Chan), but they divorced and she changed back to her maiden name of "Chang" during naturalization in 1980.

i'm assuming the only way to get to resolve the name inconsistency is through her US green card application record. I'm hoping they'll have copies of her old TW passport or some evidence of the last name stated on her old passport. It could very well have been "Chan" bc I assume TW wasn't so strict about how one romanized their names 50 years ago...

I sent a FOIA request but it was denied bc of a birth date mismatch. I want to try again, but would like to confirm with others if records of a green card application record was successful for you, or if there are better ways to resolve this issue?

She has no other TW ID except for the Household Transcript...

I would appreciate any insight immensely. I never thought the devil in the details would hit this hard, we are extremely stressed and feel a bit helpless.