Kitchener Waterloo GO would come out of the outside of GTA fund.
On a per KM basis, roughly 1/3rd of the GO budget would come outside of GTA funds (Presuming the Niagara line east of Hamilton, Barrie north of East Guilimbury, and Kitchener west of Mount Pleasant come out of the "Outside GTA" fund).
This means given the $12 Billion total cost for the entire network, on a per KM basis it should come out to roughly $8 Billion for GO. (lets go with $9 billion for safety's sake)
That leaves $6 billion for additional projects, And I would like to presume a 30% municipal contribution, meaning:
$2 billion - DRL
$1 billion - Hurontario LRT
$1 billion - Yonge Extension to Steeles (Feds and York can kick in the extra if they want for the full line)
$800 million - Hamilton LRT
$400 million - Queen BRT
$100 million - Queens Quay East LRT
$200 million - Dundas BRT to Hurontario
$250 million - Durham BRT
Total: $5.65 billion, $350 million in "wiggle room" for cost differences.