Something akin to this; yes. However, Celestia is the fantasy of fantasies. To dream of her is to walk headlong into the joyous madness that only comes unique to those who can cherish inspiration and fantasy as they do waking life. To walk the narrow tightrope that lies between delusion and inspiration.
I still think Cadence is Celestia’s daughter, and they just pretend to be aunt and niece because Cadence would rather grow up out of her mother’s shadow and Celestia would rather not be asked, ever, who the father is.