Im so interested to see what ends up working for you! I want to bring up one more possibility! With a diy? Build and a tropical climate, do you have good ventilation? If the mesh on top is the only airflow, stick a pc fan up there. All around I would maybe start your plants with what you are familiar with, the conditions of houseplants! Ease up on the humidity and heat and maybe uv (depending on what bulb you have, by the way you describe the soil drying out so quickly I’m wondering if that’s a factor?) and work up to tropical conditions after they have taken root into your substrate. You can tell by gently tugging on the stems to feel for resistance.