I can't speak for all greyhound rescues, but the two ones I volunteer for most often DO home regularly to families with small children.
As I've said previously, cat friendly greyhounds do crop up regularly - you just have to wait a little longer for them. Contact your local rescue and get yourself on to their books so they can start looking for you.
I wouldn't necessarily rule out a rescue with kennels. For example, take a look at Celia Cross Greyhound Rescue here - a highly reputable rescue that I know other MNetters have successfully adopted dogs from, and have small children. They have an extensive socialisation programme with lots of exercise, walks etc and dogs go out to store collections, meet and greets etc - a dog from here would be very thoroughly assessed in a variety of circumstances.
If you don't mind saying roughly where you are in the UK, we can point you at some good rescues.
PM me if you'd rather.
Recall. You need to bear in mind that you have a sighthound, and as such they are bred and trained to respond to visual cues often a long way away, and once they start running they are very, very fast indeed. Having said that, many greys come off the track because they aren't much good at chasing things, and with care, practice and lots of training can come off lead. As with any dog, you need to be sensible and careful. We have three - one who is brilliant off lead, one who comes off in certain, very specific circumstances while wearing a muzzle and a new foster girl (the Norty Minx) who has come straight from a working home and is therefore very keen so not allowed off lead yet, except in the greyhound field.
However, remember that you are going to be adopting a cat friendly hound, and pretty much almost by definition, if they are cat friendly, they won't have a high prey drive so are likely to be much better and safe to let off (again, subject to the usual common sense precautions).