1. Renew your license, it'll help you get a full Ontario driver's license without having to take driving lessons nor waiting - you'd have to get a partial license (only day-driving, can't drive in highways), then wait two years to get the full license. If your country's alphabet doesn't follow the roman/arabic standard, you'll need to issue an international driver's license.
2. The entire family will have the province's healthcare system (OHIP) after 90 days living in Ontario, so you'll need to buy health insurance throughout the period. Your oldest child can already go to the public school system, but you'll have to provide daycare on your own to your one-year child, and daycare is paid in Ontario. You can have financial support for daycare, but it's tax rebate or subsidy based, so you'll still have to provide some cash. I've seen daycares as low as $1000/month in Toronto, maybe a bit cheaper in smaller cities.
3. Housing costs vary a LOT in Ontario. You won't find a 2-room apartment/basement for less than $1500/month from a reliable landlord in Toronto. Ontario laws demand that you live in at least a 2-room house due to your family structure, and if your children are from opposite genders, you'll have to move to a 3-room place when the older child turns five. A 3-room in Toronto is awfully expensive (at least $2500). I highly recommend you consider living in a smaller city (Kitchener, Waterloo, Cambridge, Guelph) if you're looking for cheaper housing costs. They aren't much cheaper, either, but much lighter than Toronto. I think you still can get a 3-room apartment/house for less than $2000 in the KWC region, and the place is a nice IT job hub.
Still regarding housing, save at least $6000 for that alone. Usually you´re required to deposit the first and last month of rent, but some landlords have required three, four, even SIX months in advance if you don´t have credit history, specially in the GTA (Greater Toronto Area).
