I'd gloss Hknt-m-tp-n-nb.s as "One who praises at the head of her lord". The figure seems to me pretty clearly to be the upright composite hippopotamus/lion/crocodile type of divinity we see in Taweret, Ipy and Reret, only with a vulture's head swapped in, which is very syntactically unexceptionable. I really doubt it's an ibis head; awesome if it was, though.