Ah, I forgot to mention in my previous post that I wasn't necessarially looking to create some kind of swampy reptile/amphibian terrarium for my hams. I think bioactive was the wrong choice of words in my OP! But hopefully I think I've been able to illustrate kinda what I'm going for. At this point, taking the many words of caution, I think I'll move ahead and implement my plans but rather have it as a natural play pen instead of a permanent home.
I should also mention that my wife also lambasted me for the idea
She essentially brought up the same points as everyone else here; guess I'm too much of a naturalist for my (and hammies) own good haha. Just want to provide him some way to really scratch those natural urges and dig and dig to his heart's content.