WikiTree has comments about the link to Marisco being false genealogy (the Montorency line is the higher-level one).
https://www.wikitree.com/wiki/Montmorency-14
Geneanet's pierfit & zardoz both have his mother as Agnés d'Eû, de Soissons.
//gw.geneanet.org/pierfit?lang=fr&p=agnes&n=d+eu
//gw.geneanet.org/zardoz?lang=fr&iz=1542&p=agnes&n=de+soissons
French Wikipedia has his son Bouchard's mother as an Agnés.
https://fr.wikipedia.org/wiki/Bouchard_IV_de_Montmorency
Oops, the French Wikipedia page has Bouchard's wife as (both) Agnés,
But Medieval Lands has Bouchard's mother / Hervé's wife as Agnes.
This is enough for me to replace Alvere with Agnes.
https://fmg.ac/Projects/MedLands/PARIS%20REGION%20NOBILITY.htm#Bouc...