Your substrate issue has already been correctly addressed. As for species mixing, I'm a long time proponent of it under the right conditions. Your Copes and cricket frogs are probably good but as some have mentioned yours may not be a toad friendly environment.

As for the last statement of your original post: toads and frogs are not social animals, they do not have "buddies" and they do not have within their little brains the rather sophisticated emotional capacity for grief or joy or laughter or envy for that matter. The temptation to anthropomorphize is always great, but resist. Resist! I've been herping for about 50 years (caught my first lizard in 1963) and I have a little saying: "No matter how much of a mutual bond or kinship you feel you've developed with your toad or frog, remember one thing: If you were small enough or he were large enough he would eat you. Every time."