Jayden gives her key with a certain number of friendship points and this number is much lower than the others. It will be possible to find the key to her house in other ways, but for now,
I haven't added it yet. Jayden's sister could have a double for example
The information appears at a certain level of friendship but I believe it is given after it is possible to obtain it (I don't remember how I programmed it). If you have enough friendship and you talk to her at the right time, she gave it to you or you will have to wait for a future version to try the other way to get it. Lisa also gives the key, but at the same level of friendship as the others.
For Ava, you're busy doing the 10th quest so normally you should have gotten her key since she gives it during the 8th quest and the 9th quest takes place in the living room so it's because you've already used it.