An epiphyte is a plant that grows entirely on another plant – in other words, has no roots in the ground.
Vines and creepers are not epiphytes, because they have conventional roots in the same soil as the larger plant (or other structure) that they cling to.
I can't parse your 2nd sentence so I can't comment, but moss is not vascular and does not have roots or any mechanism to transport water internally. It just moves through the plant by capillary action.
This is the key difference between mosses and clubmosses.
Studies of temperate rain forests suggest strongly that water storage of mosses in particular allows the tree to absorb moisture directly through the bark, or in some cases form adventitious root hairs into the moss. One of the main limits to tree height is how high they can pump water through a combination of pressure and capillary action. Sequoioideae in particular have adaptations that let them push water a little higher than other trees. IIRC some of those are common to Cupressaceae (thuja plicata being the apex tree in the PNW).
We have conservationists here that have lamented the industry that has formed around harvesting moss from temperate rainforest trees. Some of these are sneaking into public lands and mass harvesting. The growth rate of these mosses barely keeps up with the rate of growth of the trees. A fully denuded tree may be dead before it's covered in mosses again.
Vines and creepers are not epiphytes, because they have conventional roots in the same soil as the larger plant (or other structure) that they cling to.
I can't parse your 2nd sentence so I can't comment, but moss is not vascular and does not have roots or any mechanism to transport water internally. It just moves through the plant by capillary action.
This is the key difference between mosses and clubmosses.