Hi Feder, you should have a good speech with the person who gave you those plants!
The first one is N. x ventrata, ok.
Then, that would be a very strange N. maxima, but with a lot of fertilizer (big leaf/small pitcher) that could even be.
Your N. "miranda" doesn't look like N. "miranda" at all, but if it's a seedgrown, home-made version of the hybrid, that could even be.
Your N. alata is another N. x ventrata.
Your N. rafflesiana from seed is N. mirabilis.
Just check google to see what I mean...
I'm sorry about that, but before those plants get spread all over your Country with the wrong name, you know...
Good luck!