Hi jammzb
I am probably considered a beginner, only having chickens for a couple of years now and you have received some really good advice to date from those with a lot more experience than I. However, as our situations are similar, I thought I would post a reply.
I also live in a built up area with neighbours very close. I have 5 Bantams, 3 are still very young and not laying yet.
My compost bin which hardly smells at all, smells more than the chicken coop and run! The only time I even remotely detect a smell is if it is has rained substantially and then it only lasts for a short while and is probably more damp earth than anything else.
I clean the coops every morning, collecting the overnight poop and give the run a good clean every weekend.
All of my grass clippings go into the run and with their constant turning it over, the poop gets buried pretty quickly.
I let my girls roam the garden (supervised due to predator possibilities) every afternoon after work and they spend most of the weekend supervised free ranging. We have a nice garden and the girls keep the weeds totally under control. All of my plants are in large pots which not only stops them from digging in them, it also gives them lots of fun places to explore around the pots, under the shade of the foliage. Yeah, I have to sweep the path every afternoon when they have gone to bed but being bantams, they are not too destructive. Plus, I have the added bonus of great compost. They have shown no interest whatsoever in jumping the fence or straying too far from their favourite spots.
My neighbours are always asking how the girls the doing and I find sharing some eggs with them adds to our mutual benefit.
For what it is worth; I totally recommend giving it a go! Not only will your kids probably get so much enjoyment out of your chickens, I reckon watching your girls mooch around in the garden is guaranteed to bring a smile to your face
And, as already mentioned, no shame in changing your mind if it doesn't work out. I bet if they were given the alternative option, your kids would make sure you have the cleanest coop and run for miles around