Long story short, the dog's fight or flight animal instinct kicked in and he attacked one of the kids, almost killing him (lots of plastic surgery, time in the ICU). 

should I go plastic or metal?

What about the plastic poison containers that protect the poison while allowing the mice to access.

It has a plastic backing that helps prevent future accidents from soaking into the carpet padding.

Worst case you could plastic the windows to get you through season and then start making a plan for replacing windows/boilers/etc in the spring.

@jim adrianalright I'll take a look at the quarter round. the dude the just helped me install the sheet laminate in the bathroom recommended plastic quarter round against the bathtub to prevent the floor from lifting, so guess that stuff is useful for all sorts of things. 

I’m screwing into plastic.

After that step, I would install a subfloor with textured plastic underneath to prevent against a minor water intrusion and go with whatever flooring you want. 

Store says no, you need water resistant pad and a plastic sheet, a barrier between the floor and the pad. 

Just make sure it is sealed probably and if you do have a stain, just use a baking soda pumice recipe and cover with plastic wrap overnight and then wipe up in the morning.