Correct, zero issue with different brands front axle and the rear duals, as long as size is the same.That, I understood. I don't think there should be an issue front to rear but I would be happier if it was confirmed that's all.
I went with the Hancocks upfront because I'm a fan of their tires and wanted a better tire on the steer axle. The Sumitomo's are great and reasonably priced 16 ply tires with a nice ride with minimal tire bounce on the rears. If I was buying all six at once like I did with my prior rig I probably would've bought 6 Sumo's