The pictures are not bad but you can see normal wear-in for a new tire. As for the info about one wearing more than the others this goes back to when you change any tire from the exact recommend size and many times type of tread its is always a good idea to get the alignment at least checked. A few platform models have had this same concern from DIY doing similar choices in the wheel and tires from original. Mazda also seems to have more interesting alignment variables when checked on the rear even when they are new on the show room floor so to say> Not sure why but that also has come up on Auto Tech forums. So getting a service shop that has an experienced alignment specialist can adjust a better alignment then as average person that just knows the service alignment steps so to say. It does however in the defense of bust shops and dealer service departments takes about 20-30 extra minutes to do a very well-done alignment. One can always tell on the final alignment reports that give the before and after. Seldom are one axle the best results possible only within specification set by the OE.

 

As long as those new 17s are 225/65R17 102V
and the rims are OE or spec you should be able to have your warranty adjudtment free - Call and ask if you were to swap the oe 19s for 17s would it be covered - proceed accordingly
- Since you said it to a bump to that wheel - definitly try regardless

 

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.....bookj1212 cover your butt do the du diligence and call the dealership and ask a hypothetical about changing your wheel and tire combo from the original. And also explain in detail what you have here on your thread about the concern for your alignment. Worst case is you can always go to an independent service shop like Firestone and get it checked and or checked and aligned.