Yes, it is an epidendrum. I would wait for the Keiki to finish flowering and start some new growth (at the expense of the mother plant) and then detach it. You should be able to snap it of, but if it is too fibrous a quick swipe with very sharp sterile shears should help remove just the keiki without damaging the main stock.
And another yes, epidendrums like this one will survive in any medium, they have very adaptable roots. They are very fast growers and once were growing like weeds in all my orchid and non-orchid pots.