I finally fixed the problem! And I can finally close this topic!
I went to friend's house and discovered that her ObiTalk account was in fact configured with username/password and NOT with Google login. So this was good news, because it meant she could give me those credentials and I will be able to remotely manage in the future.
So why do her outgoing calls display a weird caller ID, a number that looks like it might come from New Zealand and not 10 digits from USA? Answer: There was no SP selected for outgoing calls!
Two days ago she lost the ability to place outgoing calls - a robot told her she had insufficient funds. Suddenly I suspected that her outgoing calls were NOT going thru Google Voice, but instead were going thru her Anveo account that she has only for 911.
Sure enough, her ObiHai config showed that NO SP was selected for outgoing calls! SP1 is Google Voice, SP2 is Anveo. Apparently with no SP chosen for outgoing, ObiHai defaulted to the last SP in the list.
As soon as I enabled SP1 as primary for outgoing calls, all was well. No more messages about insufficient funds and caller ID is now correct.
So simple! I just don't know how the outgoing checkbox got turned off.