I have seen many people try and intermix species of reptiles/amphibians together. Honestly, I have never seen red eyes do well mixed with anything except their own species. I have seen cases when they were mixed in with Dumpy Tree Frogs. But the dumpys get significantly bigger and risk having the smaller Red eyes get picked on.
I am sure some people have mixed and have had some success, but personally I have seen nothing but disaster occur when mixing species.

Edit: if you do I would be sure each animal is checked for parasites and quarantined.