Well how long is a piece of string lol!!! At this time of year when people are arranging holidays and taking time to settle cats in, what I would suggest would be to get a home visit booked in (this is 99% about traffic flow, but when children are involved, we need to get a good idea about the household and so we can get the right kittens for you). The kids are going to grow up with the cats and therefore it's really importnat that we get this right. With a child of 3 (depending on their experience of cats before) we'd look at re-homing our 'bombproof' kittens who are wee bit older. Very young kittens are very bitey and scratchy by their very nature which as adults we don'tfeel, but it can be offputting to children. I'd suggest something around the 5/6 months where they start to walk off if they get bored, rather than bite or scratch.
We'd get the home visit ticked off and then wait a wee bit until the date was nearer and then get the whole family viewing some suitable cats and kittens. All of them are in foster care in the Leeds area and we also work closely with our sister branch in Wharfe Valley. We really work at the pace and schedule that you have and do reserve cats and kittens for people. All kittens are vet checked, de-fleaed and de-wormed and vaccinated and I really hope we can find your new family members.
If you could e-mail me at firstname.lastname@example.org with an address and contact number, I can take the enquiry further.