Need to know
#3
Hey fellow Hoosier . I found the 18x7.5 with 42 offset to be flush in the front and a snug fit in the rear so you should be fine, (I am considering a 5mm spacer on the rear to even it up.) The front will probably stick out a bit with the 45 offset.
#4
I think I have this backwards now that I think about it. positive will tuck the wheel in further. It will be a real tight fit in the rear. A good place to check it out is discounttire.com. The info section explains all the wheel/tire stuff. I'm not sure if I helped at all...I just confused you more, I fear...lol. I just find it best to go with the recommended sizes and offsets to be safe.