I am planning to buy a house in Brampton but stay in Scarborough and work in downtown.
Is it more convenient between offer acceptance till the closing if buyer lawyer is near by to the existing home? In my case what should be a preferable location for the lawyer...Brampton/Scarborough?

Get some one in your area.. Most communication is thru emails/phone... you will meet once close to the closing date to sign papers... and then on closing date to collect key...