Of course! All my examples are simulations for the purpose of creating an alternative version of our own reality. That is the usual application of simulation. To make it easier, faster, cheaper or even possible to tweak parameters in way you could not in real life and run the simulation again.

But there is nothing stopping you from being creative. You do not need to simulate "a cat", modeling it on Mrs Mittens. You can simulate the evolution of cats by starting from an Archean amoeba and tweaking the environmental factors in various ways to see what comes out the other end after 3 billion years.

Indeed. But those laws may be diametrically different from those in your own reality. Gravity can be negative.Your cat's mass may depend on the temperature.. The Sun can suck the light and heat rather than radiate it. Time can go sideways.

Of course you start from what you know but that is your own limitation, not the limitation on the possibilities of simulation.