I recommend the Dendrobates Azureus dartfrog and the golden Mantellas, they look wonderful in planted terraria and you dont need to worry a bout a pool/ pond area. Mantellas drown easy but darts take full advantage of the mini pools in the bracts of bromeliads. Both easy to feed with a home breeding programme for fruitfly/ 1 instar crickets etc.
Do pay particular attention to air circulation. so try not to overcrowd although is to easy to do so, and dramatic fluctuations in temps with the lights etc. I also do recommend highly establishing the terraria for 12-18 months first b4 amphibians are introduced. Again air flow is important to prevent saturated stagnant conditions. Water in funnels and bracts of bromeliads easily go stagnant and smell bad also causing rot probs. Some tillandsia also perish easy so investigate abit.
As for orchids the vining vanilla ideal but wise choices definetly for others. waters logged in leaf axils, bracts, sheaths, crowns kill orchids quick. Great effforts will reward you but first will be a few learning curves and trials-errors. Bondsai suppliers sell moss spores, while ficus pumila is an all too pleasing creeper with a tropical feel. Promoting the mini eco system within will serve you well. Asplenium ferns and research tropical epiphytes - planting direct in substrate will likely rot epiphyte orchid roots so a happy medium with epiphyte orchids will be better off mounted/ affixed bare. Allow the period of acclimatising to process and the roots to seek support and moisture source.
The soon to be design, planning/ arrangement that you are shortly due to commence can be step by step following advice/ experience of others. However as far as care approach goes, it is same as our open grow areas. What works for one will differ considerably to the next person. Many diff. key environmental factors exist that determine what indivduals can and cant do and theses dictate our choices. Your environmental conditions will differ in one way or many ways to anyone else even if some factors are similar.
i planted a 6ft x 3ft x 2ft all glass terrarium as a natural tropical scape half land half pool with branches situ randomly. Many plants hated it! Fans were fitted, the reptile grow lights, temps were fine.
Not intending to house ampphibians/ you can keep slightly drier! Any advice given to you or you have found will require adjustments/ improvisation and opinions and facts aplenty, only you will get to know the details. Look forward to your photo progress.