15x7 with a 3.5” backspace isn’t going to work up front. You’d have to run it like a brodozer, jacked up like a 4x4 with the wheels hanging out of the fender.
It’s not a great choice for the rear either, although it can work depending on tire selection.
I would imagine the rear would be fine with a 7" wheel. I wonder about tire selection with a 7" wheel on the front. My 72 duster has 15x6 on the front with a 205/60r15 and it looks like much taller clearance may be an issue.
I ran 15x7’s with a 225/60/15 on the front of my Duster using 4.25” backspace. Not sure what your set up looks like, but a 205/60/15 isn’t even a 25” tall wheel and should have plenty of room.