What did Toviyah do?
Malbim: He hired false Nevi'im [to make problems for Nechemyah].
Who is No'adyah?
Rashi: She is a false Nevi'yah. Ibn Ezra - this Perush is primary. "V'Gam" includes Shemayah.
Ibn Ezra citing the Meforshim: This is Shemayah. He is called No'adyah because he said No'ad (we will meet) in Beis Elokim. It says ha'Neviyah (feminine) because he was called No'adyah, a feminine form. This is like "Amrah Koheles."
What did No'adyah ha'Nevi'ah do?
Rashi: She and other false Nevi'im took wages from Sanvalat and his friends to scare me with their false Nevu'os.
Malbim: She and Shemayah prophesized that Nechemyah will be king. The other Nevi'im were hired to scare me.
