PIC 1/2) Take the moss out-dendrobiums hate the stuff. They LOVE crammed roots, and i would pot them into either broken terracotta, or a medium grade bark mix. Remember, dendrobiums are mostly used to conditions where they grow on rocks or trees. This one will like a bit more moisture than others, so water it more frequently, a good indicator is when the medium looks dry on-top.
PIC 3) This is a vanda of some description, cant tell you what though! lol
This LOVES to have open air around its roots, so dispose of most of the medium, especially that moss! Ive seen these growing in baskets with only one piece of lava rock, and the roots are metres long! very spectacular. They like high light situations, and very humid.
PIC 4)This is Epidendrum, probably Epidendrum redicans. These will grow anywhere, but again dread wet roots. Grow in a loose soil mix, bark mix or coconut fibre. Ive even seen them growing in the garden! They like high light, but no as high as vandas, and keep it out of the frosts and direct sun. It blooms about spring-time.