I wonder if maybe the way to get the commuter rail started it to walk away from it and do something else, like a series of streetcar LRT systems for the Peninsula, Mainland Halifax and Dartmouth?
These are systems which would cost much more money to build (I'm guessing in the range of about $100 million a pop, with tracks, trains and stops) but would then allow a significant focus of growth on the peninsula first? They could build 2, the routes I've suggested (Agricola and Windsor into DT) and then show how much people would want to use the system as a basis for establishing regional rail. The only catch is, if you build the streetcars and they totally fail - then regional rail would too. But I don't think that would happen...
The one thing I have agreed with from every forum member who says it; that via rail station is the saddest, under used facility ever. We have a really nice old style building that could be quite busy...if we do it right.
If you do the streetcar idea first - the lines could feed right to the train station and back into downtown; so that once you got a couple RR lines going - there was your transfer point. Depending on how far out the streetcar lines went, another transfer point could also be Mumford - this way people wanting to get to the universities or hospitals could file off at Mumford and then people for the downtown core, would get off at the train station.
If a streetcar(s) aren't done first - I would still say Mumford/Train Station would be the main connection points and you would need to have a series of buses from either point to get people to the universities/hospitals and DT core (the core from the train station only). The 8 would be a big help, but what better excuse to bring back the good old #11?

Haven't had that number in service for a while, or the 12 or 16?
So why not something like this:
Train Station Routes: 8 (existing route, increased service) plus route 11 - train station to IWK/Dalhousie and QE2 medical centre (service to SMU using route 9).
Mumford Routes: Route 12 - Mumford to QE2 medical centre/Dalhousie (robie strett) and SMU.