Would you mind telling me who WAS the first person to create all those?
No idea.
That said, you should never assume an idea you have is original.
There are many cubers in the world, and most of them aren't here on SpeedSolving ready to report the year the created some method.
One example, though: I 'created' ZZ in early 2008, before it was brought into the English-speaking world later that year.
CFOP is a very natural progression from the 'beginners' method.
Roux in various forms has been around long before 2003, in the form of Waterman-like methods.
The only interesting part of Petrus' progress is the EO step in the middle of the solve. Beyond that, the method is "make a thing, and expand it a few times."
I don't mean to discredit anyone for their work, but making a method popular by documenting it well takes possibly *more* effort than inventing a method.
I invented tons of methods, but they don't matter at all unless you document them and prove their worth.