-“Ron, you didn’t think they got that from your mother, did you?”-
That's a truly delightful line and one that's very, very plausible. It does make one wonder what Arthur did do for the DoM (I'm thinking Hit Wizard or "proactive investigator" - for which the term "reconnaisance in force" might could be used, though "reconnaisance with force" would more likely be accurate).
Author's response
Thank yeeewww! I cannot see the twins inheriting anything from Molly. Arthur is still a blank canvas, even in canon.
Here, though I will only go into his past a little bit, Arthur was at one time an unspeakable. He was captured on a mission by the Lestrange's who thought it might be fun to torture him. In the process, they cut off his legs, but did not destroy them. they were reattached after he was freed, but due to the damage, he was no longer considered fit for active duty.
(The same thing happened to me as a SEAL attached to the 1st/7th in Beirut.
After my knee was shattered, I could no longer run like I used to and so I could no longer be a SEAL. Instead of retiring me medically, like they should have,(Regan years) they decided to put me on the flight deck of the USS America.)
Alorkin
I think I got the idea on Arthur from Nightmares of Futures Past, by Viridian, but I'm not certain.