Someone PMed me, and giggled that Trel was related to Draco Malfoy... I just wanted to say this: This proves that when you are a pureblood, you will non doubtedly end up related to one another.
When I put my family tree together (on paper) it was during Trel's first term because I wanted to figure out where she lay in the timeline. She wasn't related to Draco Malfoy then as the seventh book was not out yet.
I was always fascinated with both the Greengrasses and the Notts, Purebloods that weren't mentioned in the books much. I figured Theodore Nott and Daphne Greengrass were going to end up together which is why She was in my original version and he wasn't. Draco wasn't on my radar as I thought he and Pansy would wed.
When I updated Trel's family tree (for purposes of this thread,) I remembered JK mentioned Draco did NOT infact marry Pansy, but Daphne's younger sister Asteria (or Astoria, the Lexicon was unclear.) So it really was a pleasant coincidence she's related to Draco.