And what we found out the hard way is if you can't provide something then you need to give the reason why you can't provide it.
If only one name is allowed on utilities then say you tried to get your partner added but it is not allowed by your utility company. Get utility company policy stating this.
If you don't have wills explain you are 21 and still immortal and hadn't thought about it yet.
If you don't have car insurance together explain that you don't own a car, or only one of you drives. Or that you have two different cars that you had prior to relationship and she can't drive your giant truck and you don't drive her little car... oh, wait that was us.

We had to print our text messages out of our iphones and it was amazing how much proof that really was.
Good luck we are common-law and you do have to try a bit harder.