I would take out the charcoal and sponge rock (perlite?) if you will be potting it in a place that your pet can get to. you definitely do not want them accidentally ingesting charcoal or sponge rock.
in my opinion I would put the pot in a glass container so that if anything leaches out (after fertilizing) than it cannot reach your pet.
"organic" is a tricky word that some horticulturists (like my professor) do not like to use.
I trust fox farms (which is organic), but I am not so certain about a brand like better-gro.
I never plant directly into the substrate. I always keep them in containers with their own organic soil.