Personally I don't think the fact that she included patrik in her confession instead of Rudy means much at all. The fact still stands she knew things she shouldn't have known. For instance that Meredith screamed loudly, there are 2 other witnesses that testified to hearing a blood curdling scream that night.
I also think the fact that Raffaele on hearing of Rudy Guede being arrested wrote:
"I saw father happy and smiling, but I am not 100% calm at the moment because I fear that he might invent strange things"
What strange things is Raffaele concerned Rudy would invent? One would think an innocent person would be happy as his father was that the "real" killer had been found.
Have you really read the "confessions?" They are in reality very vague. Something like a scream is the sort of think you might easily imagine to hear during a murder -- just the sort of thing that sounds descripive, but isn't really. (The reliability of the ear witnesses is another thing entirely.)