Greyhounds to Adopt, not only are you saving a dogs life but they do extensive temperament testing on their dogs to see which are good with kids, which are suitable to single dog households and any other special requirements they may have etc. The upside to getting an older dog is that you do not need to put in all of the hard work of socialising a puppy and they are much calmer, so better with young children.
Bullmastiffs are also a low energy, low maintenance breed. They do need proper socialisation at an early age but they do not need a huge backyard or a lot of exercise. They are known to prefer the couch to a walk.
Bulldogs about the same as above, low energy, low maintenance, don't require lots of exercise. Again early socialisation is important.
The other option I would suggest is going to places such as the RSPCA or local shelters/rescues and speaking to them. Tell them about your lifestyle, your family, your house and what you are looking for and they will be able to match you to a dog that more suits your needs.