Tile with epoxy grout would be my advice. We grouted this entire home using only epoxy and it is stain proof.

Lake Wood Ranch Residence · More Info

I worry that any floor with a "seam" will grab and hold onto urine. The warranty against urine "stains" is not a concern. Stain means discolouration. Loosing colour isn't the issue. The holding onto urine (the smell is what is driving the urge to mark) in the seams is the biggest problem. Anything with a seam = potential to hold urine between the planks.

You are really down to "sheet" products. Sheet vinyl, sheet lino, concrete topping, etc. Vinyl planks or vinyl tiles are all going to have issues with grabbing urine and letting it sit in the cracks.

Ceramic or porcelain tiles (as mentioned above) = great options for body fluids. The problem is the weight. Getting these heavy floors over top of a plywood subfloor = very expensive preparation (you have to reinforce the floor somehow; either reinforce the joists from below or you add layers of plywood on top to add rigidity...both are expensive and most will not go to this effort because it is cheaper to rip out low-end laminate every 5 years).

Getting sheet products over plywood = no problem. Not a lot of people want sheet vinyl in their "upper floor"...but that's what we are down to.

The other option = keep buying and replacing flooring until the pets and humans stop loosing control of bodily functions. This normally means once the people reach age "x" and sometime after the pets have moved onto another plain of existence.