Should I Remove Left Lateral Incisor for Braces (3M Clarity)?

Your best option is to see an orthodontist. It sounds like you want a nice smile and are concerned with symmetry. Having all you natural teeth even if they need to be reshaped with bonding or veneers is best. The Dr will do a diagnostic set up for you and show you how your result will look before any thing is done. Once you see the finished result and discuss with your Dr you can preceded with confidence

Here we go again..I just read the answer from a "cosmetic dentist"  by the way this is not  a recognized "specialty" by the american dental association unlike orthodontist which is.

The doctor says that extractions are "old school".  For the millionth time, extractions are just a tool, sometimes the right decision sometimes the wrong one.  Any orthodontist can treat almost every case without extractions if they wish, and truthfully, it is often easier to treat without extractions, not harder as this dentist implies. 

Having said all that, extracting lateral incisors is usually not my first choice, especially unilaterally.  Get a second or third opinion but be very careful of anyone who is dogmatic about doing things only one way!

Without photos, I can't really say, but generally speaking, extractions are a last resort.  Consider a second opinion.  Many "old school" providers are quick to remove teeth, makes the cases easier, but there are MAJOR reasons not to, including compromised aesthetics and function.

And don't buy into "lateralizing the canines".  This is a term used when the canines are moved into the lateral position, then contoured or veneered to look like a lateral.  The root eminence will make your face look imbalanced and the tooth will never look quite right.

Consider arch expansion, but often putting wires and brackets on the teeth, the alignment takes care of itself.