Sounds like the Charge Plug is good to go with just a rack, fenders, and maybe tires (and maybe calipers/rotors down the road?). Tricross sounds like it needs all that (minus the brakes) plus a new SA rear wheel and shifter. Charge would probably be cheaper to keep unless you really want to try out Sturmey Archer (though that setup on the Tricross would probably be cheaper to maintain/lower maintenance down the road from what I've heard about SA hubs - rear wheel would be heavier, but that probably won't be a concern for a commuter/JRA bike) or you decide you need the new brakes right away.