I have an 05 g35x. My car is going to be lowered soon.
I want the axis pentas in 19x8.5 F and 19x9.5 R (offsets are 35 F and 45 R).
Are these considered to be a staggered setup even tho the rims size are both 19", just the width is 1" larger.
Is it okay to run this setup on an awd car?
Does anybody know if this would fit without rulling my fenders.?
Ive read as long as the diameter of the wheel is the same it shouldnt mess up the awd system.

get same size tires and your good to go. or run specfic stag tire setup.

some AWD are running coupe wheels 8 and 8.5 wide with 245/40/19. I dont know the sizes off the top of my head for 19's but i think 255/35/19 was the rear.

Agreed. Make sure the outside diameter on front/rear are the same and you will be ok. If the diameters are different front/rear then you run risk of damaging diffs/transfer case.

So let me get this clear.
A wider rim in the rear(1" wider compared to the front), wouldnt affect the awd system if I have the same size tire all around?
What about having different offsets(35 front and 45rear)?
Is it possible to put a wider tire in the rear, while keeping the diameter the same? Would this cause a problem?

Also having this setup, is this considered a staggered.?

Wider wheels won't change outside tire diameter. It is possible to have wider tires in the rear with the same overall diameter as front. If the rears are wider but same diameter I would still consider it staggered.