Vinegar and cold water typically have no effect on modern dyes. I'm not sure how Borax might affect unset dyes. Probably if you wash with detergent and "safe for color" powdered bleach, any subsequent washes should be safe; however, you do run the risk of colors fading from the powdered bleach if any of the dye has not been properly set.
The best way to prepare the fabrics would be to wash the fabrics separately (at least, separate by color) with Retayne. Retayne will set most dyes that were incorrectly set. After using Retayne, I would also wash all 3 fabrics together and let them sit damp on top of each other for awhile to make sure that no dye is going to migrate into the other fabrics. (This is called "crocking".
An alternative would be to cut a test swatch of each fabric and submerge them in clear containers of water (such as small clear plastic water glasses). Anything that turns the water a color would need to be treated with Retayne. Also, you would want to rub each wet colored fabric against the white fabrics to make sure that dye is not transferred by contact.
I know this is more prep than you were thinking of doing, but it is the safest treatment -- especially for red fabrics. Most reds and blues these days are colorfast. I usually just test reds that I am suspicious of, then wash the quilt for the first time with Synthrapol. However, Synthrapol alone may not be enough to prevent a bad red bleeder from ruining a quilt.
If you do prewash the fabrics, you may want to starch them afterwards. Washing removes the stabilizers the factory put into the fabric; starch restores stability, making cutting and piecing more accurate.