Mercy, my ds1 has ASD and was never really interested in our dogs until we took on a rescue Lurcher pup last year. They have a really good relationship, for some reason this particular dog seems to recognise that he needs to be calm and quiet with ds1 and will just sit quietly, resting his head in his lap while he strokes him, whereas he's a real rough and tumble pup with ds2.
Ds1 has had a really hard year at school (just moved to secondary) and I honestly believe that having Pip has helped him cope. He spends a lot of time quietly stroking him and is always really pleased to see him when he gets home from school. He told us while we were away on holiday that thinking about his pup is what gets him through bad times, like when he's being bullied and we plan to put a small photo of Pip in his blazer pocket this year to reinforce that. No matter what else Pip will always be his best friend, even when he feels that he has no others.
That said, I do know of other people whose dcs with ASD haven't coped well with the disruption of having a dog in the family, although some have fared better with an older, calmer rescue than a hectic, nippy puppy.
As for general pros and cons.
Pros
I am also a SAHM and having the dogs means I have to get out of the house every day in addition to school runs (school is only across the road, so not much of a dog walk in our case).
On the odd day where I have been home before picking the dogs up from kennels after a weekend away etc I really miss them and the house feels really empty. I literally count the hours until they come home. 
They make me laugh and comfort me in equal measure though that isn't to say there haven't been tears of frustration on occasion as well.
All 3 dcs have benefitted from having dogs in different ways. Ds1 as mentioned above, ds2 has become quite the little dog trainer and it's been really good for his self-confidence, dd has learned about appropriate child/dog interaction and also to make sure she doesn't leave toys lying around. 
Cons
It does impact on your freedom in terms of long days out - but we just adapt our days to do things that the dog can do to. If we want to go somewhere like a theme park we make a weekend of it and the dogs are kennelled. I'd say we do this once or twice a year on average and that keeps everyone happy, but you do need to factor in that as an additional cost.
It also affects your freedom as a SAHM, most adult dogs (although not mine unfortunately) can be left for 2-3 hours, so long enough for a lunch or mooch around the shops, but anything longer and you'd need to arrange a dog-walker or daycare and factor in the cost.
Holidays - there are plenty of cottages that take dogs, but you may find there's a small charge in addition to the usual rental fee in some. You will also find you can't eat out while away, as the dog can't be left alone in the cottage and it's too hot for them to be left in the car during summer months. Also bear in mind dogs aren't allowed on many UK beaches during summer months, so you need to take that into consideration when planning your holidays.
Mess - no getting away from it, there will be extra cleaning. How much will depend on breed, coat type and character. Some dogs are incredibly clean by nature, others love to roll in the most disgusting thing they can find on virtually every walk and/or bring home as much mud as possible. We have a Vax Pet vaccuum which copes admirably with the fur from two scruffy Lurchers and a steam mop to tackle the never-ending footprints on the kitchen floor. Washing bedding regularly helps to stop the house smelling doggy, but if you have mainly carpet they may need regular cleaning as well. Most people with dogs reach a point where they don't really smell the doggy smell anymore, but bear in mind that visitors will still be able to smell it (not that I care).
Business - no reason why you can't run a business from home when you own a dog as long as you manage your space to comply with health and hygiene regs (usually means no pets in the kitchen) and you get him/her used to being in another room while you work.
Cost: Initial cost of purchase, pet insurance (you need life rather than annual cover, which is more expensive but worth it in case of chronic conditions), vet fees (a certain amount of vet visits will come below your insurance excess), worming and flea treatment, dog food, kennelling/day-care/dog-walker for days when you are going to be out too long to leave him/her. Initial outlay for bed, lead and collar/harness, id tag, toys, food and water bowl, plus additional vet fees for initial vaccinations and microchipping. Training and socialisation classes until you've at least mastered the basics.
I wouldn't be without my dogs for the world, but there's no getting away from the fact that they are a huge commitment and can be very expensive, so you are doing the right thing considering all the pros and cons before entering into anything.