Anjali Rajpal, DMD

You may not be aware of your grinding habit, but the generalized wear facets on your teeth are indicative of a grinding habit. That type of wear only occurs when there are excessive grinding forces. I recommend being conservative for the small chips and adding bonding/white filling material to the edges of those teeth to protect them from further wear and then wearing a bite guard at night to reduce the forces on your teeth, muscles, and jaw joints. The cold sensitivity may be from the exposed dentin which is the yellow layer under the white enamel layer. It is often hypersensitive to cold You can cover all the exposed areas with filling material.

Stay away from the major stainers- coffee, tea, red wine, cigarettes. Veneers shouldn't stain, but natural teeth and bonding do. 

Veneers can't absorb stain, which is good. However, they can't absorb bleach either. if you feel like they're getting darker there may be some leakage or something else going on so maybe just have them checked by your dentist. You may try bleaching the back part of the tooth and see if you have any success with that. 

Unlike natural teeth, or composite bonding, veneers do not absorb stain. They should stay white generally. Just stay away from abrasive polshes and toothpastes 

If you've chipped half the tooth off, bonding may not hold up that well, but you could try it first if you want to be as conservative as possible. You just may not be able to achieve as great aesthetics as you could with a veneer.
A veneer will look the best and it's still reasonably conservative. You shouldn't need to replace it for many years and you can get  a root canal through the back of the tooth without affecting the front