Yaron,
This is the first time I've seen the thread. Your description of the event, etc, is great, and quite typical of these sorts of situations. The photos you posted show that you did pretty well regardless. I'd be proud of what you achieved.
Whether film or digital, RF or SLR ... doesn't matter much in my experience. The key to succeeding at these events is knowing whatever equipment you have well, knowing the event, and working it thoroughly. The advantage of digital over film in these circumstances is that it gives you more options. Modern digital cameras have more sensitivity to work with, you can pick and choose what ISO setting works best for the situation, and you can quickly check to see whether your settings are on the mark or not.
Beyond that, you're dead right in that to get the best results you should shoot more: This is harder with film as you have to take into account the time it takes to rewind and reload, but it leads to the same goal. Shooting more doesn't mean you show a tiresome plethora of boringly similar shots, it means you have more options to choose from when selecting the 10-30 good ones. Shooting more also doesn't mean that you just press the button a bazillion times, it means you spend the same time, effort, and care on every shot—you just shoot more of them—so that you HAVE more to choose from of comparable quality.
BTW: I just don't understand comments like "I wouldn't have looked at this thread if it was on digital." That seems indicative of a closed mind, not a photographer.
I had a similar opportunity to shoot the First Communion of my partner's niece earlier this year. I had no opportunity to visit the church beforehand as they live several states away and we only had the time to fly in on Friday, attend the event on Saturday, and fly home Sunday afternoon.
I chose to bring my Olympus E-M1 rather than the M9 for this event because I knew from previous events like this that I'd need a 90mm EFoV lens for most of the shooting and the E-M1 would enable me to also capture a couple of quick videos, which the parents would enjoy. A wide and a normal*lens came along as well, but I found the portrait tele did the job best for most of the shots I made. One curious thing I found is that, because of the complexity of scenes with subjects at all distances distracting the AF system, I use manual focus most of the time—so it was really rather more like shooting with the M9 than it might seem otherwise.
I made about the same number of exposures as you did ... about 100 ... and should have made more. That said, about a dozen or so finished photos (two portraits of Michele, a stitched composite of the entire first communion group, a short video and a still of Michele in the act of receiving her communion, and a few shots of the family party afterwards) were produced which the parents and my partner were happy with. The stitched group shot made a splendid huge canvas wrap print that I sent to the mother as a birthday gift in October.
When church and event officials got in the way for a critical shot or three, I pushed past them, made the shots, and thanked them for helping me do what I went there to do. After a couple of nasty looks, they began to understand and started to actually help me get the shots I wanted. This seems to be the standard issue at all event photography that I found even when I was doing this sort of thing for a living. The photographer simply has to assert that he or she is there to do a job, not just to get in the way, and gently nudge the officials into lending a hand.
I've done many events of this type with film and digital, SLRs and RFs, over the past half-century. Be prepared, know whatever equipment you're using well, and focus on the work to be done: that's what nets the best results. You did well; I hope to see the next time you do a similar job and look forward to hearing what you have to say about it with this experience behind you.
best,
G
