Google Voice doesn't support caller ID name (CNAM). If that feature is important to you, then:
1) instead of forwarding the calls to Google Chat on your OBi device, forward them first to a SIP VoIP service provider that does offer CNAM, such as a free inbound number from Callcentric, or
2) subscribe to the new "OBiEXTRAs" fee-based service, which can do lookups of contacts' names in your Google contacts list on the fly, or, most difficult of all,
3) run your inbound number through a Asterisk-based PBX that is configured to feed numbers to a third-party CNAM provider.
And, by the way, do not forward your Verizon number TO the GV number that is being ported-into GV. That's going to cause a mess with call routing. Just wait for the port to finish, and then forward the now-GV number to whatever destinations you wish.