It may look impressive that they all say they don't allow "direct access to servers", but it's hardly surprising, since the original Guardian headline[1] was "Top-secret Prism program claims direct access to servers of firms including Google, Apple and Facebook". If they didn't say that exactly, you'd be suspicious.
It may look impressive that they all say they "haven't heard of PRISM," but this is really quite a natural thing to say if it's true, and someone accuses you of being involved in the program.
Moreover, aside from the "direct access" thing, the phrases they all use are actually different. "We have not heard of PRISM" in one case, "We have never heard of PRISM" in another, "We had not heard of a program called PRISM until yesterday," in a third, and so forth. You don't have any case for funny business based on similar wording (because it isn't), and the case for contamination based on similar content would be a whole lot more impressive if that content weren't something common and expected.
On the whole, I think the similarities have plausible mundane explanations. Admittedly, I am no student of accidental plagiarism. I don't have an academic opinion on how similar or dissimilar we should expect the statements to be when ten people try to say the same thing in response to the same accusation. But that is just my point: if you want to persuade me of something so preposterous as that all of these people are following a script, you're going to have to do more than wave your hands and say, "Look, there are similarities."
Please. That's the stuff of superstition. If you want to convince me the probability of this occurring at random is low, you're going to have to do some math.
[1] http://www.guardian.co.uk/world/2013/jun/06/us-tech-giants-n...