I think they made a huge tactical error in heading to York Landing:
The only routes in are:
1. On the ferry to Split Lake
2. Out via plane or helicopter
3. On foot, having to backtrack the way they came in.
There are no roads for traffic this time of year (there is an ice road for use in winter when the ferry doesn't run, but it seems undriveable in summer)
They are essentially stuck on the corner of the riverside backing into thick brush with likely only a few trails well known to locals, and heavily used by bears.
If they had maps, they must have misread them as York Landing is not a good place they can move forward from. They can't live from the garbage dump for very long. They are risking hugely trying to steal from people's homes or the community facilites in YL. There is no way they are getting on that ferry unnoticed.
And this is why RCMP is taking some time to assemble a force there: The ferry only holds 8 vehicles, there may be only a small boat anchorage for an RCMP vessel, the airstrip might need some sprucing up to get anything other than a bush plane in there. Best to use helicopters. They are going to take some time and effort getting their large armored vehicles in there.
There are cut-lines that could take them back NORTH to Ilford, or southwest to Kelsey. While Kelsey has a river separating it, there appears to be a ford in a narrow stretch that would be cross-able. I'd hazard a guess they are freaking out trying to find a way to escape, and there are options - but difficult to find without sat photos (these would not be on a TOPO map).
So best to send in the trackers, dogs, and sharpshooters at this point.