Sue Wendling, DMD (retired)

Your teeth are quite crowded. The teeth themselves seem very attractive. You could definitely have the illusion of straight teeth if the smile makeover is done by a very experienced dentist. Ask to see actual smile makeovers that the dentist has done himself/herself. Also, remember that the tooth preparation would be very invasive. This is a big decision. Talk with a dentist experienced in both veneers and Invisalign. 

You should see your surgeon about this and the sooner the better. The gray you see is the implant shining through the bone and gum. It most likely won't affect the implant itself but to improve the cosmetics you may need some bone or connective tissue grafting which may or may not require redoing the implant. 

That tooth has a serious problem, an infection of some kind. The root canal may need to be redone which is fairly common, or worse, you could have a vertical root fracture. See a dentist right away.

The fact that the bridge margin leaves a little tooth exposed is not a functional problem and in fact makes it easier to clean. Aesthetically, it depends on whether or not it shows when you smile. However, the only way to change the margin is to cut the bridge off and start all over. As far as the smile makeover in general, don't move forward with permanent cementation until you are completely satisfied. 

Slants(cants) are fairly difficult to correct. Sometimes a less difficult procedure can be done to at least give the illusion of correction. Looking at your smile, the two teeth either side of your two front teeth are two different lengths visually. You might consider having the shorter one lengthened. Your dentist could do what is called a "mock up" first and then snap a smile photo to see if that gives the illusion of correcting the cant.