It's a bit janky, but I'd recommend the following:

Dev Mode -> Reset Psycasts (this removes ALL psycasts)
Character Editor (mod) -> Full Heal (this removes ALL hediffs, including psylinks)

You could also use Dev Mode -> Remove Hediff to remove both Psylink hediffs.

Note: it is never a good idea to remove mods, especially ones this big, from an existing save. Even if you remove psylinks from all your colonists, there's bound to be other references to the mod and such in your file, just because the mod does so much.