We are refinishing the original hardwood floors in the 1950s house we just bought.

Here is a "before" shot (oh, the white paint splashes were the seller's attempt at "renovating" the house to sell it!):

My husband sanded off the dark-orangey-waxey finish with an orbital sander, and now they look like this:

We would like to keep them as light as possible. What would be the best finishing method to not darken or yellow the floors? We also want something durable as the kitchen has hardwoods, and something that cures quickly (ideally 3-4 days). Is there a finish that does all this?! And can we buy it at Home Depot?

To best preserve the light color, should we stain the floors with a light colored stain, or just finish them unstained?

We do have a few patches of aged cat-pee in each room, which we are assuming we can't do anything to get rid of? I've read about bleaching but concerned about discoloring around the stain...is there anything else we can try?

Does anyone know what kind of wood this is? My husband said it was very hard when sanding.

Thank you!