Cause of uneven tire wear

The outer edges of the front tires are worn out compared to the rest of the tire tread.  
The alignment has been checked several times and everything is to spec.  What other
possible reasons could cause this problem?  The service manager is suggesting I
replace the struts/shocks to fix this issue.

The rear tires show even wear.

The vehicle was in a front end collision a year ago and that's when this problem started
happening.  Car hit a tree smack in the middle of the grille.  Everything forward of the
radiator was replaced.

On a related note, after the tires were rotated, now all 4 tires show the same worn outer
edge.  However, one of the rear tires has turned into an "egg" shape such that when it
came time to rotate them again, with the "egg" shaped tire going to the front, the
resulting vibrations rendered the car undrivable.  Any speed below 30 mph causes the
steering wheel to shimmy vigorously.  Any speed over 30 mph and the whole vehicle
starts vibrating.

Again, the service tech blames a bad strut/shock for causing the tire to turn into an egg
and suggested I replace them.

Could a bad strut/shock be the cause of both these tire issues?

Thanks for any answers.