Hi and welcome to the forum. I would not mix species and I'm sure a lot of people on this forum will agree.. The species that are mixed are well thought out and mixed by experienced keepers or experts. If you want to keep red eyes they won't take up much room as they're housing is taller than wide. A 18 x 18 x 24 Exo Terra will hold a few and if you set it up as a natural planted set up you won't need to do a lot of maintenance or spending after the initial set up costs.