Deriving a Set of Seeds from a Seed
I believe it seems similar to random and urandom function in unix/Linux system. Once the physical entropy/seed is not enough, one would block and the other would generate the seed based on current ones. From security point of view, pure random entropy should be better choice, but in practical, I don't see the problem with seed generation. It should be indistinguishable to some extent if your initial seeds are pure random.. like from physical entropy.