I have only used batiks in 2 quilts, so I am no expert. What I used was yardage and I did prewash. I don't believe there was any excessive bleeding in the batiks that I used.
There was a time that I would prewash everything - would have been afraid not to. But this year I have completed 12 quilts that the fabric was not prewashed. (none of these were batik fabrics) I washed the final quilts with synthrapol and color catchers and everyone of them turned out great.
Do you have any scraps left that you run some tests with?