I think you are mostly debating against a strawman of your own construction here. The person you're responding to never claimed that "seeding the random initialization" means literally the same thing as seeding a pseudo-random number generator, and the second message was likely intended as a clarification after being misunderstood. So it's not "2 different claims" contradicting; it's a single underlying claim being expressed through a lossy medium in an increasing level of detail.

My own reading of the poster's intent aligns with this: "DNA encodes the large-scale connectivity in the brain, ie from region to region, thickness of corpus callosum etc."