I don't have any specifics about sailing that area. I have canoed in Quetico east of this area. Can certainly get windy on the bigger lakes, so I imagine Kabetogama and Rainy Lake (which are even larger) will be even more so. Of course inland winds are notoriously confusing and erratic, but I'm sure you know that.
Bears swim quite well. If they have a compelling reason to swim out to your boat
, they certainly could. As with any camping, don't give them a reason and they'll ignore you. Most bears aren't a problem anyway. It's (mainly) when they become habituated to easy food
from lazy campers that they become dangerous.
There does appear to be NOAA charts
for those lakes. At least they show up here: https://www.waterwayguide.com/explor...11&mode=marina
also has detailed charts for those areas. Of course, being CHS, they aren't free. Here's one source: https://www.nauticalchartsonline.com/charts/CHS/All
It seems clear your little sailboat would be the same as a "houseboat." They explicitly require a fee. Not sure how you'd get around that. Most inland parks in Canada
do have jurisdiction over the enclosed waterways. From the website it seems clear the same applies here.