By arts do you mean the creative arts? Unless you are gifted in your area then I strongly suggest you take a long hard look at why you would want to stake your savings and uproot your family to come here. Even if I assume that you are eventually planning to qualify for PR after completing your studies here are a few pointers basis my own experience.
Cost of living - even if it is not Vancouver, no destination in Canada can be termed affordable especially if you are currently in Asia/Africa. The 10k+4k+3k estimate for a family of 3 is a joke and is behind by atleast 3-4 years. You would easily need twice that amount unless you are willing to heavily compromise on your standard of living ie live in illegal basements, cut back on basic necessities. Unless you currently live in Australia/western europe, the cost of almost everything will come as a shock to you.
Housing - To say that there is a crisis in affordable housing in Canada is a BIG understatement, especially in Toronto and Vancouver. Expect to pay nothing less than 2.5k per month CAD for a decent ABOVE GROUND condo with utilities etc being extra. But being a new immigrant without a credit history, you will struggle to get even that and will most probably have to shell out several months rent in advance or having to settle for a compromised choice like a basement. You will find that landlords from your own national origin trying to take advantage of your situation.
Jobs - In my experience, the employment situation has been the biggest letdown. Do not believe what you read about the so called abundant job opportunities here, in certain cities, getting even a minimum wage job can be a struggle, especially if you are not so young. (I have been asked my age at a job interview to clean kitchens) Do come by all means if you are a coding whiz, in which case you will be snapped up anywhere in the world. Its true and logically should be that the part time scene is better in Tor/Van but will be offset by the insane rentals. As has been explained already, you will have to factor in steep daycare costs too.
Transportation - Most employers here require you to own a car and a clean Canadian drivers license to even consider you. But guess what, due to chip shortages, the cost of used cars are now sky high and you may have to shell out 10k plus to get one which is not falling apart. Budget for 250-300 CAD/month for insurance and the cost of gas is the highest in BC. Not all areas are served by public transport and I have observed that w/o your own car, your mobility is seriously compromised especially if you have a family.
SCAMS! Yes, I had to mention this separately since I was completely unprepared for this. As you start hunting for acco and jobs, be prepared to be bombarded by calls, texts and emails which will ask you click some shady link or download some crooked app. FB and whatsapp groups promising jobs are teeming with scamsters, so if something looks too good to betrue, it most definitely is.
So to answer your original questions, what could you reasonably expect to spend monthly unless your uni has housing available for students with families?
Rent - 1.5k atleast for 1room+den utilities incl phone plans, internet and med insurance for your spouse 300CAD + food and groceries 800CAD + transportation(insurance+gas) 300CAD Note - this is a frugal budget and most likely will be difficult to achieve in Van/Tor. Try Alberta if you can as housing is cheaper but job prospects are less in comparison. NS - same problem with affordable housing. I have not included childcare which you may need if both of you find work.
My tone has been ominous but I wanted to warn you since you are likely to burn through your savings especially if you struggle to find a job. I do not know of your personal situation and where you come from so despite the possible hardships, Canada may still represent a great possibility for a fresh start and if you are very young, you are likely to take many of these things in your stride. Everything I have said, I have experienced/observed since I have arrived here. Good luck!