Yes, you can reattach the lower lateral cartilage to the nasal spine and it will help improve your breathing. Be sure to see an experienced doctor so that they surgery is as successful as possible.
Please make sure that you protect your nose from sun exposure. Other than that, your nose should be okay to withstand being underwater and using a mask. However, try not to wear too tight of a mask to avoid crushing your nose.
Both of these grafts are capable of changing the columella lip angle. In general the columella strut graft is placed to support the nasal tip. However the tip can be attached to the strut graft in different ways to rotate the tip upward or stabilize it in its original position. That is up to the...