It's weird, I took a look at the OP's "official" IP and they have changed the tags for the Aunt, but 99% of the script still just calls her Megan, instead of Aunt or Aunt Megan. And there seems to be two tags for the same character "a" and "am", because suddenly in the chapter 5 section of the script, Megan is now suddenly Aunt Megan, lol.
I just went through and replaced any of the MC's use of "Megan" with "Aunt Megan". Threw a few "cuz's" in there for the daughters as well. It's a pretty light script so far, so it only took 5 mins.
Here's my modified script file if you wanna try it. At your own risk, lol. Just back up the original somewhere. I haven't tested this yet but it was only changes to dialogue, so it shouldn't fuck up anything important.