I think you're on the right track - the same way you're calculating the fit of the larger BS on the wider axle, you can also use the "front space" plus the axle width to see how the whole assembly will fit inside the wheel wells. You can gain an easy 1/2" per side by massaging the inner quarter panel a bit near the top of the tire.
If you aren't committed to 17's, you can probably solve some of the interference issues (UBJ zerk and OTRE) by going with 18's instead. I don't think there's a big weight penalty, and the 18" tire selection is great.
Clair