Went through same exercise few months ago, putting together keychain EDC for wife:

• Quickly learned…her willingness to actually carry dropped dramatically as bulk and weight increased. So, had to overcome my tendency to overload (like I do my own). The axiom “best equipment is what you have with you” figured prominently in final version.

• Since size/weight ruled, some utility was sacrificed.

• Ended up with: Photon Freedom; Bison small-cylinder whistle; Leatherman Micra (decent scissors her requirement); Fox keychain pepper spray ½-oz. An aside: I actually bought two of the pepper spray units, and had her discharge one to give her better feel for how it functions, what to expect from spray pattern, range etc. (been told that smaller/keychain units should be replaced annually due to unavoidable leakage of propellant over time; no firsthand experience yet).

• On plus side, she religiously carries her cell phone (and equally diligent about keeping charged). So, I wedged a folded-up $20 bill in bottom of cell phone case (and check occasionally to ensure she hasn’t “borrowed” it).

A bit beyond your scope, but I’ll also mention that hand-in-hand with this project, I undertook a campaign (training, as it were) to improve her situational awareness.

Before that, she’d been pretty much of the “that wouldn’t happen to me” school of thought. So, I started calling her attention to newspaper articles and TV news stories anytime a woman in our metro area was carjacked, assaulted, approached in a shopping center or parking garage etc. (yes, blatant scare tactics). It worked. She’s more tuned-in to her surroundings, and has a clearer idea of how she should react in a given situation.