Feel like I've spent half my time since I got my Jeep in March looking at wheels and tires.
5x127 does equal 5x5. The backspacing on those will be fine even if you go up to 35's in the future.
Tirerack lists that offset number, which is a little confusing because I think it overlaps the backspacing... Negative offset is what you want for bigger tires because it means the hub is 12mm off the centerline of the wheel toward the back... A positive offset could mess you up because it means the hub is closer to the outer centerline of the wheel. The backspacing is still the more important number.
Hope I explained that right and it makes sense, but basically those wheels are perfect.