Oh, that's right-- it's been so long since I read the books, I'd forgotten about the Graveyard Hag. Thanks for the catch! And yeah, I thought their relationship for most of the books was in a father/daughter kind of place, and then almost literally out of nowhere Pierce took it from that type of family-analogous relationship to a romantic one.
...and that's probably about 40% of the reason why I like Kel so much-- she doesn't get a Romantic Interest attached to her purely for the sake of being paired off before the end of her series.