New updates are always appreciated - please consider updating the Hybrid deployment scenario for a 2007 on-prem with 2013-based hybrid scenario, as it recently bit us with a customer during the portion where we re-pointed client access from 2007 to 2013.
If you begin the deployment the assistant with the intent to build an on-prem 2007/2013 coexistence scenario, all the proper guidance is given, including the creation of a Legacy namespace for 2007 OWA, along with updates to the internal and external URL attributes of some of the 2007 virtual directories. Under the 2007/2013 hybrid scenario, however, the assistant provides no guidance as to the configuration required on 2007 - it strictly works through the DNS and virtual directory modifications for 2013 and ignores 2007.