How does this work after the handshake network launches?

If I register a new domain with ICANN, but do not register it with Handshake, can someone else? And if not, doesn’t that mean ICANN is still the central authority for domain names? (Including transfers)

It seems like the existing root zone & handshake will immediately fork, and then how will 3rd parties determines which root zone is correct? Doesn’t that still mean existing CA’s could simply update the root zone (regardless of handshake) (which is the existing problem with bad actor CA’s).

I’m probably missing something here, could anyone elaborate?