Like the title says, are Paph. micranthum and Paph. armeniacum suitable candidates for semi hydro? I am inclined to think otherwise due to their stolon growth habit.
I'm quite certain that under the right cultural conditions, they'd do fine in S/H, but it might be a real pain to deal with the wandering nature.
Both rhizomes and roots do a really good job of growing around and through the potting medium particles, so that's probably not as much of a concern as we might think.