1) Will both my Google Voice number and CallCentric DID ring the Obi? I understand that I can set either Google Voice or CallCentric to be the 'primary' outbound line, and optionally use a ** code to choose the other service -- but will both ring? Is there any difference in the ring to indicate which is ringing?
All incoming calls ring the PHONE Port by default. The rings are identical by default, but you can select a different one at:
Voice Services -> SPx Service -> X_DefaultRing
2) Is there any decent way to test 911?
You can usually call the non-emergency number and make arrangements to make a 911 test call.
3) Are there any other 'obvious' things I should for this initial setup? Any ways to gain some additional benefit from having the second (eg CallCentric) account?
I'd say you're off to a good start. Maybe some other Callcenric users will chime in with some tips on making good use of it.