If the humidity is good for the red eyes its likely fine for the iso's. The will most likely be in the leaf litter where humidity is optimal for them. They are viv cleaners. Some people have has issues with larger Iso's like the spanish orange eating on plants but i haven't seen it. There is usually plenty for them to eat in the bottom of the viv,
I actually keep my Iso cultures a little drier than my spring cultures. They tend to do better in lighter media and get around and reproduce more,

Michael