I'm not sure this will help you but, I like to keep it simple with my contacts.
I store them on the phone only (choosing the backup assistant option). Since I never activated backup assistant my contacts are only store on the phone. I don't sync to Google or Verizon. Whenever I make changes to my contacts I back them up to the sd card.
I never have any problems with contacts.
But you should be able to enter on the computer rather than the phone.
verizon/backup assistant & gmail won't duplicate contacts.
i use ba as primary backup but everything i put into gmail/contacts also gets to the phone.
I just discovered I had "display only names with phone numbers". This sort of prevents seeing all the names. It doesn't help with the mixup on my son's contact but re entering the whole thing did.