It's odd using the new application form for a childs passport renewal, but that's how the system works. To simplify the process, one parent should be the "applicant" and the other parent the "guarantor". (Passport agents are going to want to verify that both parents are aware of the passport application anyways.)
I renewed DD's passport on Monday. I went in to the passport office with:
* completed forms, signed by me (applicant) and wife (guarantor)
* passport photos of DD (one signed by wife/guarantor)
* DD's birth certificate
* DD's expiring passport
* my photo ID (passport or drivers license)
* payment (credit card)
I was in and out in less than 30 minutes (Calgary office). Now is a good time of year to apply for passports. The typical rush season is in late fall, as people plan and book winter get-aways. (I have nighmares about 2.5 hours lost in downtown Ottawa. 1 hour in Surrey was more reasonable, but still not as efficient as Calgary.)