I'd call Crutchfield. They have been very helpful to me. As far as inputs front/back, You can probably use Bluetooth f0r music from your phone and so only need USB. I routed my USB cable down to my console (or yo can put it in your glovebox). I have two cars with Kenwood Excelon receivers and like them a lot.
2011 F150 4X4, 5.0, SCAB, Lbed, HD Payload Package, Blue Flame Metallic, ARE Shell, Front - JL Audio C5-525, Rear - Kappa 602.11cfX4, Dually reverse lights, Dually high beams, DD3, Kenwood DNX890 with Maestro, NVX MVPA4 and MVPA1, JL Audio 10TW3 subwooofer in custom cabinet, Billnvic HIDs, RCI Metalworks skidplates, heated front seats, AMP steps.