First of all, neither of you understand what an absolute freak Cordia is. She sits around in her bondage gear sipping the finest of teas while watching the MC on the cameras SHE had set up in his room and bathroom. She totally understands the MC's voyeuristic tendencies and doesn't hold them against him.
As for Gracie being a no-go or her most precious thing...eh, and no. Cordia is far more protective of Gracie, or so it seems outwardly, yes, but that's because of what happened to Luna. She knows Luna's been through some shit and that she essentially turned into a weapon, but I don't believe she loves her any less because of it. If she hates anyone it's herself (and obviously those responsible of course) for "allowing" it to happen.
She lets Luna "Luna", because that's the only way she can have any semblance of happiness. I mean, can you imagine Luna being cooped up like a bird in a cage? She's end up blowing up the mansion or something. There's no way in hell she'd ever be able to relax and have anything like a normal life until she gets her revenge. After that she'd still be Luna, but with the MC's help she'd be more accepting of "soft" things.
And since Cordia wants the MC to be a part of the family, I don't really think she'd mind if he and the girls go together, as long as it was a healthy relationship for all parties involved. She isn't some innocent flower or anything, so in the event she doesn't know about the cameras, if she found out I could see a conversation along the lines of "Well, I understand. Just don't do anything perverted. And if you hurt my babies I'll cut your fucking eyes out and feed them to you."
*takes a sip of tea*
Anyway, that's just how I see things / my opinion. Only Hopes know for sure.