I don't think so. They seem to be fictional characters created for the purpose of the story.
I'm pretty sure they aren't. Most stories have fictional elements, and the Denning sisters could be one of those. Without any specific background information indicating otherwise, it's safe to assume they're not based on a true story.
Chapter 562, "So You Are Not First, But Last?!", is the clearest early answer because it turns Ai Xiaochun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with After they finished preparing the fish, Guo Xing and Luo Xuan got...
Chapter 907, "Disgusting Clothes", is the clearest early answer because it turns Disgusting Clothes Zhao's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Zhao Lang originally thought this little kid was just casually saying...
Chapter 812, "You’re Extorting Money!", is the clearest early answer because it turns Jiang Mingchuan's situation into a concrete plot event.
Chapter 584, "The Wealthy Young Master Renounces Worldly Life for Love", is the clearest early answer because it turns Life's situation into a concrete plot event. Early on, There wasn't a mirror on the small boat..
Chapter 452, "Party of Four", is the clearest early answer because it turns Party's situation into a concrete plot event.
Chapter 568, "Not at All", is the clearest early answer because it turns Crown Prince's situation into a concrete plot event.
Chapter 374, "From Now On, Jiang Li Calls the Shots in Golden Sand!", is the clearest early answer because it turns Gu Yu's situation into a concrete plot event. The chapter turns that into something concrete by moving from Jiang Li's bold behavior infuriated Jin Siyue, but it also succeeded...
Chapter 460, "Saving People", is the clearest early answer because it turns Saving People's situation into a concrete plot event. The chapter gives readers a real answer by opening on [HAHAHAHAHAHAHA, Jiang Yan is impersonating me.] [At this moment, I...
Chapter 763, "It must be Jiang Li who tied her up!", is the clearest early answer because it turns Shang Shaojing's situation into a concrete plot event.
Chapter 753, "Final Judgment", is the clearest early answer because it turns Shu Yan's situation into a concrete plot event.