To me, it doesn't matter what Donna's occupation was when she met Felicity's father, if said father is Damien Darhk. It's the idea of him taking an evil sabbatical to go play house for a few years that makes me LOL. And, obviously getting involved in some low-level crime while he was there, since Donna and Felicity's hospital talk insinuated that they knew he was a criminal.
It reminds me of Steve Martin's character in My Blue Heaven, who leaves the mob by going into the witness protection program, only to start a small-town crime ring by scamming people out of change donations to help sick children, haha.