For a start I do not own any KWG shares so am not a source of information about that company. Nor do I have any insider info regarding the two railway paths.
What I did read from a posting, I think on this forum, a while back when the Moosonee railway was introduced that the federal government was all for it ( It may have been Chief Martin saying so).

Personally while being all for the Noront road I have no particular preference for either railway. I do note that the Moosonee-Timmins path may be more favourable to Noront because of the ready facilities in Timmins.
Also the Moosonee terminus could be extended some day along the Hudson's Bay all the way to Churchill. So with long view of the future this has some possibilities. Note that costlines tend to be settled and developed before interiors.
While the KWG-Aroland one is shorter therefore presumably cheaper to build and thus more practical for chromite transport.

Finally I think both rail options are seriously considered but with Matawa doing the infrastructure study, well we must know what they are most likely to be in favour of.