That happened to me once...ended up burning through a pair of new BFGs on my Foxbody. Thought I could run it lowered for a minute until alignment. Turns out I desperately needed camber plates to get the amount necessary to keep the tires properly aligned
Blown struts would be more apt to create uneven wear in a pattern, and they dont hold the car up, the springs do, so even if they are shot, they shouldnt really make the tire wear that way exclusively.
Different size tires are not going to blow your diffs. A cars tires spin at different speeds and distances all the time just by turning more one way than the other ect ect. The only downside is safety and different amounts of grip and traction typically.