If you firm your plans to go in the route I suggested, be sure to do a search on the lakes you'll be traveling thru.

There are numerous trip reports that hold info about that route.
I don't think you'll lack for campsites or fishing going that way.
Badwater is a destination for some coming out of Beaverhouse becasue of it's rep as a walleye lake.

That time of year it shouldn't be an issue as you'll be passing thru.
If you don't exit via Maligne to LLC village, I consider going back thru Jean Creek/ Jean lk and west down Quetico lk.

You can make it to Jean lk easily in a short day and depending on wind, even make it to the east end of Quetico in a long day. From there you should have wind at your back, and a nice ride back to Beaverhouse.

Search that route in trip reports, lot's of good info there.