NDA's are not the same across the board, they're different for each contract, though typically a company will use similar ones again, so we can at least assume a little that the timing of when it can be disclosed, for nintendo, is when it's announced, since Yatch Club was able to talk about Shovel Knight after he was revealed.
This is close to what
TheCJBrine
mentioned.
This will most likely be important to note for nintendo contracts. but other than that it's hard to say exactly what cristina's voicing projects are and if it's just for smash. That said, it's safe to assume she'd be under one even for an assist trophy, so who knows really. (in the case she's the voice actress)
Yeah. It's normal to play devil's advocate in order to strengthen theories. It helps to get good information as concrete as possible, making sure that what's thought to be the case is in line with the reality of things. It's like putting your equipment to the test, stress-testing it to see if it works well.
That said, a lot of times it's better to make it a bit more clear that you're not opposing someone or their views but just countering to test the theories.
Not everyone likes to feel like their views are being opposed, especially if they're attached to them or are sensitive.
But yes in general when someone is comfortable it can be good to verify and be able to strengthen a view so that it holds well.