Based on this answer, there is plenty of evidence that malachim can be human. There is a widespread opinion that the 3 visitors who came to Avraham were malachim. Are there any opinions who agree that they were malachim, but say that some or all of them were human malachim, rather than the supernatural type? ie. that they were normal human beings who Hashem was using as agents of His will (whether or not they were aware of that)?
אָמַר רַבִּי תַּנְחוּמָא אָמַר רַבִּי לֵוִי אַבְרָהָם שֶׁהָיָה כֹּחוֹ יָפֶה נִדְמוּ לוֹ בִּדְמוּת אֲנָשִׁים, אֲבָל לוֹט עַל יְדֵי שֶׁהָיָה כֹּחוֹ רַע נִדְמוּ לוֹ בִּדְמוּת מַלְאָכִים
Rabbi Tancḥuma said that Rabbi Levi said: To Avraham, whose power was great, they appeared in the image of men; to Lot, whose strength was inferior, they appeared in the image of angels.
The Eitz Yosef there explains this to mean that Avraham was accustomed to seeing angels, and so they appeared to him as men, yet with Lot who was not used to seeing angels, they appeared as angels.