Yes, all true, but besides the point, since the bugs where planted at the begging of the game before any feelings developed, also, it doesn't matter if it wasn't a normal contract, he is a prisoner non the less, he didn't want to be part of this life, he was good where he was, so yes although it being a weird contract has allowed the situation to come to where it is, but it doesn't change the fact that he is a prisoner to it
From MC's point of view, in the beginning everyone was a complete stranger, but from Cordia's point of view, I think there is certain degree of affection/respect that already exists towards the MC that didn't exist with the other members of the Family.
She's the one who orders MC to be treated well (to everyone's confusion), and it's due to her wishes that MC gets to dine together with the rest of the Family members. She even asks to MC there how he feels and whether he's been treated well.
She could have just given him a meal and told him to eat by himself (or with other typical "employees under contract" of DeLucas) without joining the Family for dinner because he's not their blood.
Also, there's the fact that Antonio mentions that Cordia was furious to find out someone tried to poison the MC as well.
Perhaps this soft spot Cordia has for MC has to do with her own past friendship with MC's mom Rina. Or it could also be her mysterious past with MC's father. We won't know until much later. But it's certain Cordia went through great lengths to make sure MC is treated well.
Don't know about you, but for me, I'm getting the feeling the whole "Forced Contract" with the MC is just semantics to her to keep MC around (though I just don't think there's any nefarious plan in design regarding the MC from her to be honest).
As to why Cordia would be disappointed? Well, you can only be disappointed in someone when you know that person, and you have certain expectations regarding that person. Cordia is finding out more about MC with him spending time with everyone in the Family, and with her free-roam event approaching (possibly after Eiza's sister story update is done? Though who knows), she will spend more time with MC and get closer with him.
If Cordia caught a run-of-the-mill employee who was using bugs to spy on the Family, then she wouldn't care about the employee at all (unless that person was close to Cordia herself), & would have no problem seeing the person eliminated.
But it's MC that is being looked at here. I just see the whole "He is a prisoner" aspect of the forced contract as mere technicality at this point.
And with MC basically developing great relationship with all the girls (including Cordia), if MC gets caught doing something she (Cordia) does not approve, I think she'd be disappointed (if the player chose audio, she'd be more understanding, and while disappointed, may be more forgiving like her catching MC red-handed in her office situation.
Though if the player chose the cameras, I doubt she'll be as lenient especially with MC going "peeping Tom" mode on her girls).
p.s. I think I'm just gonna leave this debate here. It was fun and all, but I think we're basically going around in circles with this. And I'd rather finish this with "Let's just agree to disagree."