I most defintely think that she is the proginor of the bennett witch family line. Out of all the witches in this series processor shane has not only studied bonnie's family heritage but also helped restored bonnie's powers as well, and gave her the talisman that belong to quetsiyah herself.
I personally thought all along that Quetsiyah is a Bennett. When Bonnie was channeling energy from the old Gilbert mansion, there was mention of some things that I want to say give indication that there is more to the witches on the other side than was being outwardly indicated. This makes me want to go back and watch those episodes again, because I thought it was known that she was a Bennett witch, and that is why Bonnie was needed by Shane... but I could be wrong, I watched the whole first 3 seasons in like 2 weeks on netflix so I didn't ever get a chance to absorb anything, I just jumped into the next episode.
I've been thinking the same thing it would also explain how Esthter come to be with the spell to begin with so there is a big possibility that Bonnie is decended from her. If so then if Silas is awakened he could want revenge on Bonnie for Qetsiyah's imprisionment of him