I've been thinking about this a lot, and came across an idea. Why would *any* WCV learn to be a spellcaster?!? It's too direct for them. Only a pitiful, weak WCV would do anything so direct. Instead, they'd use catspaws. Like harry to get their magical dirty work done. So, while it's possible, just not fitting, theme-wise.
Though there is no reason they couldn't. It's just a matter if you decide to "attach" it to feeding dependency or not.