I got past the earlier error. Now setup detects an incomplete installation and promises to continue only to fail immediately in "Mailbox Role: Transport service" with the following error:
The following error was generated when "$error.Clear();
set-ExchangeServerRole -Identity $RoleFqdnOrName -IsHubTransportServer:$true -DomainController $RoleDomainController
" was run: "Property IsHubTransportServer can't be set on this object because it requires the object to have version 0.1 (8.0.535.0) or later. The object's current version is 0.0 (6.5.6500.0).".
I found similar errors relating to Exchange 2010 (in fact one of the sad bits of all this is all the problems people have with 2013 also happened on 2010) and people muttered about IP V6 but I didn't see any comment that appeared to be relevant. This error appears to be a version error, of some sort.
Why is Exchange so difficult? Any program that is this much trouble should be free, not several hundred dollars!