Hi kitty, I've never owned a kitten/cat myself so may not be qualified to answer, but I reckon if your DH really wants it, works from home, and has promised to be the primary carer(!) then perhaps it's okay? I'm sure your youngest will be gentle with it if you explain how small(and cuddly, soft, cute, adorable) a kitten is? With next door's cat being due in a few weeks, could it be fate?
go on, i think it is sweet how a grown man wants a kitten as long as he changes the litter tray you are fine and it is good for th kids. i have a 16 month old and two cats as well as a dog and my boy adores them all. i have to tell him to be gentle as he does not realise they are as hardy as the dog! what have you to lose? though must supervise the children with the kitten for scratches and rough kiddies. kittens are quite hyper once they settle in.
my ds is fine with cat they tend to hide themselves away if the world gets too much and you woul donly have to say no nice ds has never intentionally tried to be rough at all his 3 and had cat since he was born
Cats aren't much work really - just house training the kitten, then throwing away the dead creatures they bring into the house from time to time. My only concern would be having a cat when you have a baby as I've heard stories about the cat jumping in the cot and having jealous fits.
We always had at least one cat with our babies, no problems to speak of and we had a cot net, they used to be available from the NCT rather like a tennis net sized mesh which the cat will not jump on, unlike a fine mesh. If you can trust him to keep his word about cleaning up let him have the kitten, it will give him so much pleasure and your dc's will love it too.