I think you're on the right track and I wouldnt get too extensive with it since you (i assume) want it to be small and easy to carry so that it is actually with them when needed. IMO, of the things you listed these are most important (in order of importance) items and they are also the ones I would include if it were me. duct tape and paracord and other such items are certainly nice for everyday use but this is an urban escape kit (right?) and IMHO I say keep it small and light ans stick with the essentials.

Flashlight
FAK
Aqua blox
whistle
bandanna
Dust Mask