1) If there's no visible wear on the cam lobes AND you're ok with the performance of a stock cam then there's no reason not to reuse it.
2)
Assuming that all pistons/bores/connecting rod bearings are the same size then it shouldn't matter which rod is in which cylinder- they're only marked so that each rod cap stays with its rod. (if it'll help you sleep better at night then by all means, put them in order

)
3) I would definitely step up to better rings; moly, chrome, or whatever floats your boat. The cheap "rebuilder" iron rings can/will wear the bore fairly quickly.
I'd also look at the valve stem seals- it likely has the "old school" cheap poly-acrylate umbrella seals that will harden & fail in a couple years. There are better materials & designs available.
Work a small amount of petroleum jelly into the oil pump rotors- this will help them seal & prime during start-up.