I do not wash batiks, but I do test ones I am suspicious of. I have had very few bleed over the years, but it may depend on the type of batik. Most of mine are commercial yardage. I think that hand-dyes are much more likely to bleed.
When using Retayne, make sure that you use lots of water (front-loaders are not good for this job) and hot water. You can group like colors and do them in the sink, if you like.
I personally would not use Retayne on pre-cut batik strips because of the risk of shrinkage. I would test them, though.
To test, drop a small piece of the fabric into a glass of water and wait for an hour or so to see if dye seeps into the water (bleeding). Also, rub both dry and damp fabric against a white fabric to see if any dye transfers (crocking). If a fabric passes both of these tests, it is safe to use in a quilt (for me, anyway).
One last thing I do is make sure to wash the quilt the first time in Synthrapol, which suspends any unset dye particles in water so they don't settle in other fabrics. Again, for Synthrapol you need lots of hot water (not a home front loading machine). Also, you must not allow the damp quilt to sit on itself; it needs to be removed immediately and either laid out to dry or dried in a tumbling dryer. This is to prevent dye transfer from one wet fabric to another.