If your new leaves start to turn yellow, the first thing to check is the amount of light your orchid is receiving If light is not a problem, then check to see if you orchid is being subjected to low temperatures. If you are growing your orchid in bark medium, ensure the fertilizer you are using is high in nitrogen. Bark tends to rob orchids of their nitrogen thus turning the leaves yellow. There are also orchids that will lose all of their leaves naturally like the Dendrobium nobiles. No matter what you do, you will not be able to keep all of the roots in a pot.
Orchids love to send roots out looking for things to attach to.
This is their way of life. These are not an orchid. Without seeing the actual orchid, all I can do is guess what genera your orchid belongs to. Figuring out what particular species the orchid may be is very difficult without extensive study of the plant over an extended period of time. If the orchid is a hybrid, it could be impossible to determine the specific parents that were used in the crosses.