HI,
I'm wondering if most people bring one or two pairs of hiking footwear? Shoes and hiking sandal? 2 pairs of shoes? etc.
I take two pairs of shoes, but I'm not most people. Full disclosure, I have three pairs. Shoes and socks are the items that get the carte blanche treatment in my pack weight budget.
I walk in running shoes for the most part. For 90% of the trail, running shoes are fine. I also carry a set of gortex hiking shoes, which I change into when a) its raining, b) the rougher parts of the trail like the descent into Acebo, c) when my feet request a change of footwear. This third pair are nearly weightless crocs for use in the albergues. There are the less-than-perfect weeks where I change my shoes every few hours as the weather and trail change. There are sunny weeks where the hiking shoes are so much dead weight on my back. So be it.
As an aside, gortex shoes are no panacea for wet weather, your feet will still get wet. But they do buy you an hour of comfort when the rain starts or stops, or the trail is muddy. In most cases, that's all you really need, because the weather and the trail change. On rainout days, I do what everyone else does: slog along in soggy misery, or head for shelter until it stops.
As others have said, most people carry a walking set plus an albergue spare. I find that the ability to change shoes on the trail is worth the extra weight in the pack. This is not a calculation that should be made lightly, as pack weight is a huge factor in having a great versus miserable experience during your camino. My math says that the ability to change shoes on demand has a better overall outcome than taking a kilo out of my pack. For most people, this is not true. You will need to find out for yourself where your preferences lie.
Buen Camino