I engaged in a similar project at Kangaroo Point in Brisbane. If legend is true, the original bollard locations were marked out by members of the Brisbane Rockclimbing Club in chalk and the contractors who were installing them progressively went along and installed them. Apparently it then rained, meaning in some places the chalk washed away and nothing was installed. Additionally, whilst well meaning, its pretty clear that the climbers at the time simply put a bollard to service the existing routes (or possibly just a selection thereof) meaning that later routes were dificult or impossible to set a top-rope on.
The first thing I think you guys volunteering to help should do is to map out some plans. Don't get too drawn into simply adding a second bolt in whatever location the first bolt was placed, but rather take a more holistic approach and think about what anchor array will best serve the area for the next 25-50 years.
Sketch yourself some maps, draw on where the climbs are, then get out and walk it and see how an anchor set-up will work on each of the climbs.
With regard to hardware choice, being inner-city you've got to assume you're going to get a pretty mixed bag of users, so you want something which is highly resistant to vandalism and to 'improper' use. I'd be looking at glue-in rings or U-bolts in 12mm stock using epoxy (powers fast pro, ramset 801/reo502, etc).