A couple of comments keeping in mind your "With this backpack I'm envisioning her being stuck somewhere in the metropolitan area -- at work, a store or on a road -- and having to walk all or much of the way home. Probably 10-15 miles." comment.

NAVIGATION:
*Replace the button compass with a hikers baseplate compass. The additional weight and bulk is more then offset by increased accuracy and quality.
*Earbuds consume a lot less power then external speakers on radios. The minimal cost, bulk, and weight of a pair of basic ones will be offset by the extended battery life.

FIRST AID:
*She's may be covering a lot of distance on foot. Athletic tape, second skin, and mole skin will cut down on foot and knee strain and blisters.

FOOD:
*Add in salty simple carbohydrates (i.e. pretzels) for on the move energy. High protien and fat foods tend to sit in your stomach while you're moving

TOOLS:
*Replace the FB knife, seat belt cutter, and mini-leatherman with a medium or full size Leatherman or SAK. There's not much need for a FB knife in urban/suburban environs, the seatbelt cutter function is already made redundant by EMT shears, and the mini-leathermans are light to medium use only. A medium or full size MT or SAK is going to provide the most punch for it's bulk.

MISC:
*Duct tape (gear repair - like shoes)
*Pocket hone
*Cell charger (If the radio has a jack for a 5-6V AC adaptor, it can also be run off of a 5V USB power source using an adaptor)

HOME:
*Strap any tall furniture to the wall. You spend more time at home then at work. So, your chances of getting squashed to death under a toppled bookshelf or dresser is better then at your desk.