You probably know this already, given the historical society component.
https://en.m.wikipedia.org/wiki/Frick_(surname)#:~:text=Frick%20is%20a%20German%20shortening,(born%201948)%2C%20Liechtenstein%20politician
Search Frick Wiki yourself cause I got an additional page to that one above that listed way more notables in history but it won't copy the link properly for me, from a Civil War Union officer to a South African chess player.
That list has some pretty amusing notables, including Frick and Frack (even though not their real names)..
The obvious is that 'frick' is a well known euphemism for a word my husband (and half the world) uses on a regular basis, but you want to keep it clean.
Frick rhymes with Crick, you could go that route.
Maybe the name was originally Crick but was illegible on paper and they got stuck with it and have had to endure jokes at their expense all their life, cause of their Daddy's bad handwriting. Maybe he was a German immigrant and had no idea what the name changed to, or preferred the more Anglo Crick.
One of the girls could mention Frick, Crick, that neither is better than the other, given their slang meanings.
Maybe someone could pipe up with famous and notable Fricks in history.
Some further context might help.
Can you post a little of what you've written already to give us a sense of character and what you're going for?
Of course there's also Trick. Lucky the girls didn't get lumped with that one.
And I almost forgot Watson & Crick and Franklin and the DNA discussion.