Stag 5 declaration a question for the experts as I prepare

I am preparing a StAG 5 (Declaration) application. My grandmother was a German citizen who married a British citizen in 1947, thereby losing her citizenship under the discriminatory laws of the time. I am the descendant seeking restoration. The "Chain of Evidence": The Root Ancestor (Great-Grandmother): * Caroline Mina Emma Kadel, born approx. 1895–1900 in Germany. I do not have her birth certificate it however I have other evidence (Vorfahrengeburt vor 1914 auf deutschem Boden) as she was a resident giving birth in Germany in 1921 to my Grandmother Hermine Elisabeth Dühr, born June 9, 1921, in Iserlohn. Crucial Legal Status: My grans birth record explicitly states she was born "Uneheliche Tochter" (out of wedlock). Logic: Per RuStAG 1913, as an illegitimate child, she legally and exclusively acquired her German citizenship from her mother (Caroline).

Also a "Status Transfer" to my Aunt

There is a handwritten marginal note (Randvermerk) on my grandmother's 1921 record from Iserlohn. It references the birth of her first daughter (my aunt) in Essen on Nov 12, 1946 The note labels my aunt as "Uneheliche Tochter". This note suggests that in late 1946 just months before her 1947 Scottish marriage to my Scottish grandfather—the German state officially recognized my grandmother as a German citizen capable of passing status to an out-of-wedlock child.

The then Loss my grandmothers citizenship My grandmother married my grandfather (British) in 1947 in Scotland. She became Hermine Coyle. This is the event that triggered the loss of her German citizenship.

The Claimant (Me): My father was born to her after the 1947 marriage in Scotland. Under the new StAG 5 rules, we are eligible to declare citizenship.

The deep Questions for the Experts: Given the "Uneheliche" status in 1921 and the 1946 marginal note confirming she was still passing German status to her children in Essen, will the BVA still insist on finding the 1890s birth certificate for the great-grandmother (Caroline)?

Is the 1946 marginal note on the 1921 birth certificate in Iserlohn record considered "strong evidence" of her status at that time, or should I still order the full 1946 Essen birth record for my aunt? To get more evidence on my great grandparents? Specifically my great grandmother.