In this case, I don't think it has to do with marriage, as Elizabeth is still named Huddleston when she marries Brayton Read in 1799. Also, if she was married, I think the will would've just referred to her as Elizabeth Sisson as was the usual way at that time.
my question was more geared towards her childhood - was she of a different marriage, was she illegiimate, or merely, was she being taken care of by the Sisson family that were her cousins growing up, and was sometimes referred to by that name, or even she may have been adopted - either formally or casually. I'm just hoping there's a way I can find out a little more about what may have been the situation. clearly, there is some reason she's referenced in a bit of a different way when she's been mentioned.