I wouldn't keep the bird with leakage unless it ends up having phenomenal type, but that's just me. If you breed a bird with leakage, you'll be culling more of its offspring for the same reason.
The other two, I'd keep and breed together to see what they produce. I had a blue cockerel that started out the same way, with a couple of white feathers here and there. As he matured, he developed more and more white feathers, like a mottled colored bird. That's exactly what I had planned to do with him, try to start some mottled Silkies. Sadly, something got himI'll post some pics of him later (when my daughter gets off the computer), its hard to share them from my phone!
Edited to add pictures:
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Omg he is beautiful! I love him! Like a reverse paint. Just wow.