Heather strikes me as more a 2nd mother figure to Lyric than a traditional aunt figure. Perhaps that is why TB is listed as Lyric's "favorite" aunt.
I find naming any relative the deceased's favorite "insert title here" odd but I can see where Heather might not be viewed by Lyric as an "aunt" but as something more maternal than that.
I could see that in other circumstances. But Heather and Misty aren't speaking and haven't been for months. To me, it seems an obvious dig at Heather by Misty.