After careful research into the matter of what to call/how to refer to Elizabeth Wilson and Lori Stevens, it seems the more accurate terms that do the least bit of harm among parents is "genetic donor" and "birth mother".
Technically, Lori is biologically related to the twins, but she does not fill the mother role as per the definition to the both of them. Even though she raised Carter as her own for so many years, to avoid confusion and keep things as adequately accurate as possible, it may be best to refer to Lori as the Wilsons' "genetic donor" and Elizabeth as the twins' "birth mother". Thus when referring to the twins' parents, either "the Wilson parents" or "birth mother and biological father", because Elizabeth wouldn't be the girls' adoptive mom—even though she isn't biologically related, she gave birth to the girls, and there is a strict egg donor contract…
Mothers who use egg donors also don't consider the donors to be "mothers" at all and see their children produced by egg donors' eggs to be their own.
My goal was to find a socially acceptable way to refer to the two women without causing any uproar to parents themselves.
If anyone has any opinions regarding this, I'm open ears!