hi I also have two indoor terrariums in my living room to the quiet dismay of my long -suffering wife
I found them in garage sales, and a picture been easier than my imperfect english, there you go.
I have found that two large box-case computer fans work well and are perfectly silent... i have each on one side one on top, one at bottom, near the bottom one i put orchids like masdevallias that enjoy the cooler air.
I found that even for botanical phalaenopsis the light that came with the terrarium was not sufficient and i had to install a ramp of four t5 neons. Even the juvenile phals are eager for light it seems!
As far as humidity and heat are concerned, I use both a heating pad like the one they have for reptiles which i put under the terrarium, but only on one part of it as some of the orchids in there prefer a cooler floor, i have clay pellets on the bottom floor too with a amount of water. i also have used an exterior mister with a fan connected to the hose of an vacuum cleaner ( see second picture )
i have punctured some holes on the hose for a repartition of the mist all along the terrarium. timers run all the system, at night only the fans are running but i must emphasize they only produce a very moderate air movement. I have about 30 plants in there... never bothered to count really
Anyway I do not wish to overload your post, good luck with your installation.