Generally speaking, pets need the same things people need:
Shelter
Warmth in low temps
Water
Food
Meds & first aid
Identification

And, because they're not rational thinkers, confinement of some kind. A collapsible wire dog crate for cats would be handy, a vinyl-covered steel cable for the dog.

A litter box could come in handy for cats, but you could use all kinds of stuff for the litter: dirt, sand, ashes (cold), small or crumpled dry leaves. A scoop, too.

You're probably aware that shelters don't accept animals. This is just beginning to change, but don't count on it. I rather camp in the car with the pets rather than leave them behind.

Sue