With thanks to @Deusovi for solving the Masyus and doing the hard part.
If you overlay the Masyu solutions on the Nurikabe solution, you will find something interesting:
You notice that
So to make this Masyu more colorful, you should probably do this:
There, much better.
Partial answer - stuck on extraction
Solution to the Nurikabe:
What else is going on?
I'm not sure what to do next; overlaying the solutions to the logic puzzles doesn't look like anything useful. (And the fact that the 4×4 doesn't appear to work is surprising...)