Can't be a Dendrochilum - they're all Asian and have pendant flwoer spikes. It appears from the picture to be a Stelis species.
#3 appears to be Maxillaria (don't know all the new names for the splits in that genus)
#4 a Stelis species
#5 an Epidendrum, possibly macrostachum (not sure I have that spelled correctly)
#6 my guess is an Odonotglossum, though I do not know what species.