Is that rubbing just on the very tip of the bumper? If it is, then you can do what I did, and just push the splash guard back and cut the angle of the bumper and it goes away entirely.
And I agree with you on the E rated tires, that was my primary reason for avoiding the new Falken Wildpeaks, as in our 245 size they're only available in E.
Oh and it's not the end of the world keeping the 245s for a bit, you can get some excellent flex, and they tuck into the fenders extremely well:
Plus the Duratracs are excellent tires, so it's not like you're stuck with some junk Michelin M/S tires (what mine had when I got it, complete POSs).
Perhaps it's like the new Power Wagon, which is only sold with 33s even though 35s would easily fit, just because you can get the maximum flex with smaller tires. It is a balance between ground clearance and flex I suppose, at least the new lift will get the front end, which is what seems to me to be what scrapes the most, a little higher.
Looking great as usual.