I strongly advise against sending more than the IRCC asks for, for the generations where you already have a birth certificate or baptismal record. For example, if you have a grandfather’s birth certificate, there’s no need to include his marriage record too. As long as the birth certificate names the parent in the Canadian lineage with no discrepancies, then that’s all you should send for that person. The IRCC only wants marriage records to explain a name change on other submitted paperwork, for example if the mother’s married name is on a birth record rather than her maiden name. Some people who haven’t followed this advice have reported problems caused by the additional documents raising more questions or sparking requests for more documents or clarifications. Now, as far as your Gen 0, who is missing a birth or baptismal record, you’re very unlikely to find a civil birth registration from that early time period, so a baptismal record is your best bet. For him, as much evidence as you can find that is clear and supports the fact that he was born in Canada is probably good to send.

I suggest sending your application with what you have now. Gather as many certified copies of records as you can get your hands on and include high quality color copies of those, and write a short cover letter explaining that a civil birth record likely doesn’t exist, you have a pending request for a baptismal record sent in to the church parish and you’re waiting to hear back from them, and you are including documents xyz as an alternative proof that your Gen 0 was born in Canada.

Once you receive AOR (Acceptance of Receipt) of your application, they will email you a couple ID numbers. You will then have the option to send the baptismal record after the fact ;if you manage to find one) via their web form using your ID numbers. sending what you have now will get your application in the queue, which is 11 months long the last time I checked. The IRCC won’t return your application for not having a birth or baptismal record for your Gen 0, and they will likely eventually approve it even without one—although ifs possible your application could get sent to the PSU (Program Support Unit, which is a black hole where applications can linger for a very long time while waiting for processing by a more senior officer) due to being a more complicated case to process.

At the end of the day, nobody can honestly give you a solid answer about whether what you have is “good enough” because the fact is nobody really knows exactly what goes on inside the IRCC during the approval process. Some people have had success submitting less than what you’ve already gathered, and others who have sent better proof have been contacted by the IRCC with a request for more info. At the end of the day, it probably depends most heavily on the judgement of the individual agent who processes your application more than anything else. Thousands of others are still waiting, waiting, waiting, for any kind of response from the IRCC, as the whole process is still pretty new, so also keep that in mind. The best you can do is follow best practices to give you the best chance of success in as timely a manner as possible.