Regular townies turning into spellcasters?

Question: (I'm not super knowledgeable on how the townie system works in TS4) If I went through and marked any sim I don't want in the Magic Realm as played (for example, I'd have no problem if the Goth family was walking around but no thank you Nancy Landgraab, you can't be here) will they be safe from showing up there? If the game generates new, probably ugly, townies to hang out in the realm that's fine with me. I can fix them.