as far as the rims go: It is a great idea to replace them with alloy. As far as replacing the whole wheel or the rim goes, the front one is a no: brainer: Get a new wheel with alloy rim and hub and a quick release. It will make your life easier. Finding an 120mm spaced rear wheel with an alloy hub with quick release that can accommodate your 5sp freewheel will be more challenging, but well worth it. Will be about the cost of getting an alloy rim and rebuilding the wheel with your steel hub, but will be lighter (because of the hub) and more functional.

About the pedals: Hard to tell from the pictures, but there are generic plastic cages and staps that go for about $15 or so a pair. If they fit, that's probably the way to go.

It looks like a '75'-'76. Nice bikes, the have a really nice ride but heavy. Great commuters. There is space for a rack and fenders if you want to go that way. Enjoy it!