Yes, there is a reason why zoos only put together displays of animals from the same ecosystem, and in fairly large cages. It doesn't sound to me like all of your species are compatible, and some of them may end in danger sooner or later. Additionally, we don't know how long you've had this set-up, so if the veiled is only about 6-7 months old, wait until she's full grown and starts taking interest in larger prey. I find that the eyes on my girls are bigger than their stomachs, and if allowed, they will shoot for the single largest male roach in the whole colony, and not the more moderately sized nymph you'd think she'd go for!
However, you've received enough comments on the mixing of species. On to the soil question. I do and have used soil from Lowe's almost exclusively in my vivariums, particularly their organic (perlite- and fertilizer-free) soils and topsoils, which never contain anything except small pieces of wood or moss. This, set over a layer of the hydroballs (separated by a layer of window screening or something similar) is a very simple way to set up the ground in a vivarium. Just make sure there are no little perlite balls, fertilizers, or insecticides. Then you plant whatever plants you want into the layer of soil and you're good to go.
That said, I don't use soil on the floor of my chameleon cages for the sake of cleanliness, but I do with all my other reptiles. But this is the same soil I use in the laying bins of my females, which I do keep in the cage at all times, or at least most of the time. It does well for laying as well, I find, and even better when mixed with just a little washed play sand. Because you have a female veiled, do you have any way to make a 12" layer of substrate or provide a much deeper laying container for when she does need to lay eggs?
i agree. 
that kind of worries me 
