15x7 4.25 backspacing on the front. Does it work?

Does the galaxy tire make a 215/65r15? That’s about the biggest and tallest that will fit on the front (also a 225/60r15 should too). If those are your only choices on the galaxy I would say to use the 215/60’s

If you’re switching to 7" rims then you’ll want to keep the backspacing 4-4.25". If they stick out too far it can make the tire hit the bottom front portion of the fender. The back can be tight too all pending the tire size