I decided not to chance the potting soil. A friend has some unused eco earth that they're able to drop by soon. I'm thinking three inches or so of that?
I got some fresh green leaves off a little baby oak tree in my yard. I rinsed them in very hot water and took off any oddities, and now I'll freeze them for an hour or so. I have yet to find any cholla in stores or order any, so while that's on my bucket list, I figure I'll use the oak branches for now so they can climb.
With regards to bark, what kinds of trees are safe and how would I debug it before adding it? I'm thinking instead I could use cardboard, I've seen some people who keep isopods using it. Does it have to be a special kind, or just any old cardboard, i.e. paper towel rolls?
Also, how many isopods can I comfortably house in the ten gallon?
And yeah, we got lucky. For us it was better than ordering them and tons more fun. Our backyard is tiny and surpringly we found all of them in the grass. We had the best luck in the evening when they all start coming out. My brother laughed at the two of us, kneeling on the cement of the patio and looking through the grass, but hey, it worked. Even got some cool colors and patterns.
My mom is surprisingly okay with the rolly pollies (probably because we always had a bucket full as kids that we'd show her and then release). But she's like your mom, she really doesn't dig the crabs. In her own words "anything that lives in the sea and has an exoskeleton creeps her out". She says they look like giant bugs. I tried to convince her that they don't live in the sea so she shouldn't be scared of them, but she wasn't having it.
Oak is always a hit! 
