How long will porcelain veneers stay clean and unstained? I drink coffee and tea daily and red wine often. Will the veneers stain faster than my real teeth? Can they be cleaned if they do stain (like real teeth can)?

Shouldn't stain. They should not stain. However the bonding at the edges might and the tooth to which they are bonded might. Always practice optimum oral hygiene to help prevent this.
Long time. Porcelain veneers are actually more stain resistant than natural teeth because they are not porous. However, depending upon how much coffee and red wine you drink they will, over time, pick up stain. A professional cleaning will remove that stain for you.
No. Veneers stain slower than your own teeth. Coffee, wine, .... Stain your own teeth a lot faster than veneers, and yes if they get stained they can be polished off.
It depends... The porcelain itself will not stain. However, if the junction between the porcelain and your teeth is visible, that line or junction may stain. The better the dentist does with his technique the longer this junction will last without staining.
If . If they are porcelain veneers the material itself will not stain. However the adhesive used to attach the veneer to the tooth can stain. As such choose a dentist who demands an exact fit from his/her laboratory and uses state of the art adhesives.
Yes. Brush and floss well. Especially after eating and wine drinking. If you still get staining, your dentist can polish and bleach.