My profile is very basic and pretty much just a lot of snippets of code thrown together by trial and error as I know nothing about coding. So what I'm looking for would be something along the lines of "hidepet=id" that I can just try and squeeze in with the rest of the mess to prevent certain pets from showing. Does anything like that exist?

yeah, you should be able to use {display:none;} (pet_0 is the first one on the list, then the second is pet_1, and so on)

i would move whoever you want to hide to the end via the pet order page, if possible, because in my experience the remaining pets don't move to fill in the gap, it just leaves an empty square

That's exactly what I was looking for, thank you!