PMO & Mushkegowuk Council's:
That is not much of a rival because the transportation route involves ( Mind you, just my uninformed opinion ) a bit more cost to build if it involves railway and comparing to KWG's shortest N/S. This is due to longer path.

Where it has merit above KWG rail and Noront road combination is if they include a smelter at Attawapiscat, or no further than Moose Factory. With a sea port at either location one could easily ship metal to eastern coast of N. America and Europe, cornering a good portion of those markets.

Of course for smelter they would have to get that Quebec hydro power ( shorter distance).

That means just the rail line to the Hudson's Bay, continuing to Timmins.
What ever path railway takes, the Noront E/W road still needed to serve the most communities for services and supplies. Probably built before any rail ways.

That is a heavy dose of combinations to hurdle over. Without all those parts coming together, this idea has little chance of progressing further. And I think a combination of it was examined some years ago, I think even by Noront's feasibility studies.