Lauraeli, I want to encourage you to consider micro-miniature orchids in the future. I was also hesitant, but with the encouragement of Orchid Board members, I was able to create a beautiful orchid terrarium with three micro-miniatures, two of which have bloomed already. I love my terrarium as much as my full sized orchids!
They are so cute! With a little more knowledge, I may have to! Do you have pictures of your terrarium/micro-minis?
I would say the greatest challenge is ensuring that the micro-mini's selected will all work together. I eventually replaced one of the orchids because it needed more sun than the terrarium can tolerate because of the potential heat build-up.