I believe that all ideas for fiction come from real life. After all, where else would we get them? Real life is what we know. One can, of course, argue in favor of divine inspiration, but that's included in my view of real life: "all things visible and invisible." Some ideas are drawn deliberately from real life, but most are filtered through the writer's subconscious, which can produce some very strange stories indeed.
The fact that something resembles a real person or entity, however, does not mean that particular reality was necessarily the source. Correlation is not the same as cause and effect. Sometimes ideas just seem to be in the air, and different writers will write about the same idea at approximately the same time.
For an example of cause and effect: I once contributed to an anthology, In Celebration of Lammas Night, based on Mercedes Lackey's filk song Lammas Night. Nineteen writers started from the same place, but the stories were as individual as the writers. Misty's story, Hallowmas Night, and mine, Midsummer Folly, are both available as eBooks, if you want to see how much two people can diverge from a single idea. The song serves as the cause, and the stories are the effect.
An example of correlation would be the Free Amazon/Renunciate Guild Houses in Marion Zimmer Bradley's Darkover novels The Saga of the Renunciates (The Shattered Chain, Thendara House, and City of Sorcery) and the Beguines. Somebody once sent Marion a copy of a paper which referred to "Marion Zimmer Bradley's unacknowledged debt to the Beguines." The reason this "debt" was unacknowledged was that Marion had never heard of the Beguines. She derived her Guild House rules from the Rules used in Christian convents. If you are looking for a way for a large group of women to live together in relative harmony, convents provide a model that has worked for many centuries.
In fiction, especially science fiction and fantasy, something may walk like a duck and quack like a duck without actually being a duck.